Optical image measuring apparatus, image displaying apparatus and image displaying method

ABSTRACT

An optical system splits light into signal light and reference light and detects interference light between scattered light of signal light from living body and reference light. A scanner performs first scan in which first cross section that intersects interested blood vessel is repeatedly scanned with signal light. An image forming part forms first cross sectional image expressing chronological variation of morphology of first cross section and phase image expressing chronological variation of phase difference based on detection results of interference light acquired during first scan. A blood vessel region specifying part specifies blood vessel region corresponding to interested blood vessel for first cross sectional image and phase image. A blood flow information generator generates blood flow information related to interested blood vessel based on blood vessel region of first cross sectional image and chronological variation of phase difference within blood vessel region of phase image.

TECHNICAL FIELD

The present invention relates to a blood flow measuring technology inwhich optical coherence tomography (OCT) is used.

BACKGROUND TECHNOLOGY

In recent years, OCT that forms images of the surface morphology andinternal morphology of an object by using a light beam from a laserlight source or the like has attracted attention. Unlike an X-ray CTapparatus, optical coherence tomography is noninvasive to human bodies,and is therefore expected to be utilized in the medical field andbiological field. For example, in the ophthalmology, apparatuses thatform images of a fundus and cornea or the like are in a practical stage.

The apparatus disclosed in Patent Document 1 uses a technique ofso-called “Fourier Domain OCT.” That is to say, the apparatus irradiatesa low-coherence light beam to an object, superposes the reflected lightand the reference light to generate an interference light, and acquiresthe spectral intensity distribution of the interference light to executeFourier transform, thereby imaging the morphology in the depth direction(the z-direction) of the object. Furthermore, the apparatus is providedwith a galvano mirror that scans a light beam (signal light) along onedirection (x-direction) perpendicular to the z-direction, and is therebyconfigured to form an image of a desired measurement target region ofthe object. An image formed by this apparatus is a two-dimensional crosssectional image in the depth direction (z-direction) along the scanningdirection (x-direction) of the light beam. The technique of this type isalso called Spectral Domain.

Patent Document 2 discloses a technique of scanning with a signal lightin the horizontal direction (x-direction) and the vertical direction(y-direction) to form multiple two-dimensional cross sectional images inthe horizontal direction, and acquiring and imaging three-dimensionalcross sectional information of a measured range based on the crosssectional images. As the three-dimensional imaging, for example, amethod of arranging and displaying multiple cross sectional images inthe vertical direction (referred to as stack data or the like), or amethod of executing a rendering process on volume data (voxel data)based on stack data to form a three-dimensional image may be considered.

Patent Documents 3 and 4 disclose other types of OCT apparatuses. PatentDocument 3 describes an OCT apparatus that images the morphology of anobject by sweeping the wavelength of light that is irradiated to anobject (wavelength sweeping), detecting interference light obtained bysuperposing the reflected lights of the light of the respectivewavelengths on the reference light to acquire its spectral intensitydistribution, and executing Fourier transform. Such an OCT apparatus iscalled a Swept Source type or the like. The Swept Source type is a kindof the Fourier Domain type.

Further, Patent Document 4 describes an OCT device that irradiates alight having a predetermined beam diameter to an object and analyzes thecomponents of an interference light obtained by superposing thereflected light and the reference light, thereby forming an image of theobject in a cross-section orthogonal to the travelling direction of thelight. Such an OCT device is called a full-field type, en-face type orthe like.

Patent Document 5 discloses an example of applying OCT to theophthalmologic field. It should be noted that, before OCT was applied, aretinal camera, a slit lamp microscope, etc. were used as apparatusesfor observing an eye (see Patent Documents 6 and 7, for example). Theretinal camera is an apparatus that photographs the fundus by projectingillumination light onto the eye and receiving the reflected light fromthe fundus. The slit lamp microscope is an apparatus that obtains animage of the cross-section of the cornea by cutting off the lightsection of the cornea using slit light.

The apparatus with OCT is superior relative to the retinal camera, etc.in that high-definition images can be obtained, further in that crosssectional images and three-dimensional images can be obtained, etc.

Thus, the apparatus using OCT can be used for observation of variousregions of the eye and is capable of obtaining high-definition images,and therefore, has been applied to the diagnosis of various ophthalmicdisorders.

Further, OCT is used not only in measurement of morphology of an objectbut also blood flow measurement of blood that flows in a blood vessel ina living body (see Patent Documents 8 and 9, for example). The bloodflow measurement that uses OCT is applied to measurement of eye fundusblood flow etc.

PRIOR ART DOCUMENTS Patent Documents

[Patent Document 1]

-   Japanese Unexamined Patent Application Publication No. H11-325849    [Patent Document 2]-   Japanese Unexamined Patent Application Publication No. 2002-139421    [Patent Document 3]-   Japanese Unexamined Patent Application Publication No. 2007-24677    [Patent Document 4]-   Japanese Unexamined Patent Application Publication No. 2006-153838    [Patent Document 5]-   Japanese Unexamined Patent Application Publication No. 2008-73099    [Patent Document 6]-   Japanese Unexamined Patent Application Publication No. H09-276232    [Patent Document 7]-   Japanese Unexamined Patent Application Publication No. 2008-259544    [Patent Document 8]-   Japanese Unexamined Patent Application Publication No. 2009-165710    [Patent Document 9]-   Japanese Unexamined Patent Application Publication No. 2010-523286

SUMMARY OF THE INVENTION Problem that the Invention is to Solve

Since there are cases in which the change of blood flow occurs in earlydiseases, it can be thought that blood flow measurement may be used fordiagnosis thereof. However, it is difficult for conventional blood flowmeasurement to achieve sufficient accuracy for early diagnosis.

Thus, a purpose of the present invention is to provide a technology thatis capable of carrying out blood flow measurement with high accuracy.

Further, conventional image display apparatuses etc. have a problem thatmultiple images required to measure blood flow cannot be displayedadequately.

For example, there is no conventional technology for associating a crosssectional image, phase image and blood flow information required tomeasure blood flow information and for displaying them simultaneously.For this reason, conventional technology cannot obtain measurement stateetc. of blood flow information adequately by utilizing images requiredfor blood flow measurement.

Means for Solving the Problem

The present invention is an optical image measuring apparatus thatcomprises: an optical system configured to split light from a lightsource into signal light and reference light, and detect interferencelight between scattered light of the signal light from a living body andthe reference light having traveled by way of a reference optical path;a scanner configured to carry out a first scan in which a first crosssection that intersects an interested blood vessel in the living body isrepeatedly scanned with the signal light; an image forming partconfigured to form a first cross sectional image that expresseschronological variation of morphology of the first cross section and aphase image that expresses chronological variation of phase differencebased on the detection results of the interference light acquired by theoptical system during the first scan; a blood vessel region specifyingpart configured to specify a blood vessel region corresponding to theinterested blood vessel for each of the first cross sectional image andthe phase image; and a blood flow information generating part configuredto generate blood flow information related to the interested bloodvessel based on the blood vessel region of the first cross sectionalimage and the chronological variation of phase difference within theblood vessel region of the phase image.

Effect of the Invention

According to the present invention, blood flow measurement with highaccuracy can be realized because the present invention is configured tocarry out blood flow measurement by using a first cross sectional imageat the same cross section as a phase image and chronological variationof phase difference.

Further, according to the present invention, blood flow measurement maybe carried out by using a first cross sectional image at the same crosssection as a phase image and chronological variation of phasedifference. Moreover, the present invention functions to calculate bloodflow velocity based on chronological variation of phase difference andspecification result of blood vessel region, calculate diameter of bloodvessel of interest based on photographed image, and calculate blood flowbased on calculation result of the blood flow velocity and thecalculation result of the blood vessel diameter. Therefore, blood flowmeasurement with high accuracy can be realized.

Further, according to the present invention, it is possible to displaymultiple images required for blood flow measurement adequately.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an example of configuration of afundus observation apparatus (optical image measuring apparatus)according to an embodiment.

FIG. 2 is a schematic diagram showing an example of a configuration of afundus observation apparatus according to an embodiment.

FIG. 3 is a schematic block diagram showing an example of the presentconfiguration.

FIG. 4 is a schematic block diagram showing an example of the presentconfiguration.

FIG. 5 is a schematic diagram showing an example of the presentoperation.

FIG. 6 is a schematic diagram showing an example of the presentoperation.

FIG. 7 is a flowchart showing the present operation.

FIG. 8 is a schematic diagram showing an example of a configuration ofan image displaying apparatus according to an embodiment.

FIG. 9 is a flowchart for explaining the present operation.

FIG. 10 is a flowchart for explaining the present operation.

FIG. 11 is a conceptual diagram of the present embodiment.

FIG. 12 is a diagram showing an example of a living body image of thepresent embodiment.

FIG. 13 is a diagram showing an example of living body image managementinformation of the present embodiment.

FIG. 14 is a diagram showing an example of blood vessel managementinformation of the present embodiment.

FIG. 15 is a diagram showing an example of a cross sectional image ofthe present embodiment.

FIG. 16 is a diagram showing an example of cross section managementinformation of the present embodiment.

FIG. 17 is a diagram showing an example of cross section blood vesselmanagement information of the present embodiment.

FIG. 18 is a diagram showing an example of a phase image of the presentembodiment.

FIG. 19 is a diagram showing an example of phase management informationof the present embodiment.

FIG. 20 is a diagram showing an example of phase blood vessel managementinformation of the present embodiment.

FIG. 21 is a diagram showing an example of blood flow informationmanagement information of the present embodiment.

FIG. 22 is a diagram showing an example of display of the presentembodiment.

FIG. 23 is a diagram showing an example of display of the presentembodiment.

FIG. 24 is a diagram showing an example of display of the presentembodiment.

FIG. 25 is a diagram showing an example of display of the presentembodiment.

FIG. 26 is a diagram showing an example of display of the presentembodiment.

FIG. 27 is a diagram showing an example of display of the presentembodiment.

FIG. 28 is a diagram showing an example of display of the presentembodiment.

FIG. 29 is a diagram showing an example of blood vessel classificationmanagement information of the present embodiment.

FIG. 30 is a diagram showing an example of display of the presentembodiment.

FIG. 31 is a schematic diagram showing an example of the appearance of acomputer that realizes an image displaying apparatus of the presentembodiment.

FIG. 32 is a diagram showing an example of an internal configuration ofthe present embodiment.

MODE FOR CARRYING OUT THE INVENTION

Examples of embodiments an optical image measuring apparatus accordingto the present invention will be described in detail with reference tothe drawings. An optical image measuring apparatus according to thepresent invention forms a cross sectional image and three-dimensionalimage of a living body by using OCT. In the present description, imagesobtained by OCT are sometimes referred to as OCT images. Furthermore, ameasuring action for forming an OCT image is sometimes referred to asOCT measurement. It should be noted that the contents described in thedocuments cited in this description may be applied to the followingembodiments.

In the following embodiments, an eye (fundus) is regarded as ameasurement target of a living body, and a fundus observation apparatusis described in which OCT measurement of the fundus is carried out byemploying Fourier Domain OCT. Particularly, the fundus observationapparatus according to the following embodiments is capable of obtainingboth a fundus OCT image with Spectral Domain OCT and a fundus image,which is similar to the apparatus disclosed in Patent Document 5. Itshould be noted that configurations according to the present inventionmay be applied to a fundus observation apparatus of any type other thanSpectral Domain (for example, Swept Source OCT). Further, apparatuses inwhich an OCT apparatus and a retinal camera are combined are explainedin the embodiments; however, it is possible to combine an OCT apparatuscomprising configuration according to the embodiments with a fundusimaging apparatus of any type, such as an SLO (Scanning LaserOphthalmoscope), slit lamp microscope, ophthalmologic surgicalmicroscope, etc. Further, configurations of the embodiment may beincorporated with a single-functional OCT apparatus. Moreover, it ispossible to apply the configurations of the embodiments to OCTapparatuses that measure biological sites other than eye fundus. Suchbiological sites may be arbitrary sites that can be targets of examiningstates of blood flow.

[Configurations]

A fundus observation apparatus 1, as shown in FIG. 1, includes a retinalcamera unit 2, an OCT unit 100, and an arithmetic and control unit 200.The retinal camera unit 2 has almost the same optical system as aconventional retinal camera. The OCT unit 100 is provided with anoptical system for obtaining an OCT image of a fundus. The arithmeticand control unit 200 is provided with a computer that executes variousarithmetic processes, control processes, and so on.

[Retinal Camera Unit]

The retinal camera unit 2 shown in FIG. 1 is provided with an opticalsystem for forming a 2-dimensional image (fundus image) representing thesurface morphology of the fundus Ef of an eye E. Fundus images includeobservation images, photographed images, etc. The observation image is,for example, a monochromatic moving image formed at a prescribed framerate using near-infrared light. The photographed image may be, forexample, a color image captured by flashing visible light, or amonochromatic still image captured by using near-infrared light orvisible light as illumination light. The retinal camera unit 2 may alsobe configured to be capable of capturing other types of images such as afluorescein angiography image, an indocyanine green fluorescent image,and an autofluorescent image.

The retinal camera unit 2 is provided with a chin rest and a foreheadplacement for supporting the face of the subject. Moreover, the retinalcamera unit 2 is provided with the illumination optical system 10 andthe imaging optical system 30. The illumination optical system 10irradiates illumination light to the fundus Ef. The imaging opticalsystem 30 guides a fundus reflected light of the illumination light toimaging devices (CCD image sensors 35, 38 (sometimes referred to simplyas CCD)). Moreover, the imaging optical system 30 guides signal lightinput from the OCT unit 100 to the fundus Ef, and guides the signallight returned from the fundus Ef to the OCT unit 100.

An observation light source 11 of the illumination optical system 10comprises, for example, a halogen lamp. Light (observation illuminationlight) output from the observation light source 11 is reflected by areflection mirror 12 with a curved reflection surface, and becomesnear-infrared after passing through a visible cut filter 14 via acondenser lens 13. Furthermore, the observation illumination light isonce converged near an imaging light source 15, reflected by a mirror16, and passes through relay lenses 17 and 18, a diaphragm 19, and arelay lens 20. Then, the observation illumination light is reflected onthe peripheral part (the surrounding region of an aperture part) of anaperture mirror 21, transmitted through a dichroic mirror 46, andrefracted by an object lens 22, thereby illuminating the fundus Ef. Itshould be noted that LED (Light Emitting Diode) may be used as theobservation light source.

The fundus reflection light of the observation illumination light isrefracted by the object lens 22, transmitted through the dichroic mirror46, passes through the aperture part formed in the center region of theaperture mirror 21, transmitted through a dichroic mirror 55, travelsthrough a focusing lens 31, and reflected by a mirror 32. Furthermore,the fundus reflection light is transmitted through a half-mirror 40,refracted by reflected by a dichroic mirror 33, and forms an image onthe light receiving surface of the CCD image sensor 35 by a condenserlens 34. The CCD image sensor 35 detects the fundus reflection light ata preset frame rate, for example. An image (observation image) based onthe fundus reflection light detected by the CCD image sensor 35 isdisplayed on a display device 3. It should be noted that when theimaging optical system is focused on the anterior eye part, theobservation image of the anterior eye part of the eye E is displayed.

The imaging light source 15 comprises, for example, a xenon lamp. Thelight (imaging illumination light) output from the imaging light source15 is irradiated to the fundus Ef via the same route as that of theobservation illumination light. The fundus reflection light of theimaging illumination light is guided to the dichroic mirror 33 via thesame route as that of the observation illumination light, transmittedthrough the dichroic mirror 33, reflected by a mirror 36, and forms animage on the light receiving surface of the CCD image sensor 38 by acondenser lens 37. An image (photographed image) based on the fundusreflection light detected by the CCD image sensor 38 is displayed on thedisplay device 3. It should be noted that the display device 3 fordisplaying the observation image and the display device 3 for displayingthe photographed image may be the same or different. Further, whensimilar photographing is carried out by illuminating the eye E withinfrared light, infrared photographed image is displayed. Moreover, LEDmay be used as the imaging light source.

An LCD (Liquid Crystal Display) 39 displays a fixation target or atarget for measuring visual acuity. The fixation target is a visualtarget for fixating the eye E, and is used when photographing a fundusor performing OCT measurement.

Part of the light output from the LCD 39 is reflected by the half-mirror40, reflected by the mirror 32, passes through the aperture part of theaperture mirror 21, refracted by the object lens 22, and projected ontothe fundus Ef.

By changing a display position of the fixation target on the screen ofthe LCD 39, it is possible to change the fixation position of the eye E.Examples of the fixation positions of the eye E include the position foracquiring an image centered at the macula of the fundus Ef, the positionfor acquiring an image centered at the optic papilla, the position foracquiring an image centered at the fundus center located between themacula and the optic papilla, and so on, as in conventional retinalcameras. Further, the display position of the fixation target may bearbitrarily changed.

Furthermore, as with conventional retinal cameras, the retinal cameraunit 2 is provided with an alignment optical system 50 and a focusoptical system 60. The alignment optical system 50 generates a target(alignment target) for matching the position (alignment) of the deviceoptical system with respect to the eye E. The focus optical system 60generates a target (split target) for matching the focus with respect tothe eye Ef.

Light (alignment light) output from an LED 51 of the alignment opticalsystem 50 passes through diaphragms 52 and 53 and a relay lens 54, isreflected by the dichroic mirror 55, passes through the aperture part ofthe aperture mirror 21, is transmitted through the dichroic mirror 46,and is projected onto the cornea of the eye E by the object lens 22.

Cornea reflection light of the alignment light passes through the objectlens 22, the dichroic mirror 46 and the aperture part, a part of thecornea reflection light is transmitted through the dichroic mirror 55,passes through the focusing lens 31, reflected by the mirror 32,transmitted through the half-mirror 40, reflected by the dichroic mirror33, and projected onto the light receiving surface of the CCD imagesensor 35 by the condenser lens 34. An image (alignment target) capturedby the CCD image sensor 35 is displayed on the display device 3 togetherwith the observation image. The user conducts alignment by an operationthat is the same as conventional retinal cameras. Further, alignment maybe performed in a way in which the arithmetic and control unit 200analyzes the position of the alignment target and controls the movementof the optical system (automatic alignment function).

In order to conduct focus adjustment, the reflection surface of areflection rod 67 is positioned at a slanted position on the opticalpath of the illumination optical system 10. Light (focus light) outputfrom an LED 61 of the focus optical system 60 passes through a relaylens 62, is split into two light fluxes by a split target plate 63,passes through a two-hole diaphragm 64, is reflected by a mirror 65, andis reflected after an image is formed once on the reflection surface ofthe reflection rod 67 by a condenser lens 66. Furthermore, the focuslight passes through the relay lens 20, is reflected at the aperturemirror 21, is transmitted through the dichroic mirror 46, is refractedby the object lens 22, and is projected onto the fundus Ef.

The fundus reflection light of the focus light passes through the sameroute as the cornea reflection light of the alignment light and isdetected by the CCD image sensor 35. An image (split target) captured bythe CCD image sensor 35 is displayed on the display device 3 togetherwith the observation image. The arithmetic and control unit 200, as inthe conventional technology, analyzes the position of the split target,and moves the focusing lens 31 and the focus optical system 60 forfocusing (automatic focusing function). Further, focusing may beperformed manually while visually recognizing the split target.

The dichroic mirror 46 splits the optical path for OCT from the opticalfor eye fundus photographing. More specifically, the optical path forfundus photography and the optical path for OCT measurement areconfigured to be coaxial and share the optical path on the eye E side ofthe dichroic mirror 46. The dichroic mirror 46 reflects light of thewavelength band used for OCT, and transmits the light for eye fundusphotographing. The optical path for OCT is provided with a collimatorlens unit 40, an optical path length changing part 41, a galvano scanner42, a focusing lens 43, a mirror 44 and a relay lens 45.

The optical path length changing part 41 is capable of moving in thedirection indicated by the arrow in FIG. 1 to change the length of theoptical path for OCT. This change of optical path length may be used forcorrection of the optical path length in accordance with the axiallength of the eye E, and for adjustment of the condition ofinterference. The optical path length changing part 41 is configured tocomprise a corner cube and a mechanism for moving the corner cube, forexample.

The galvano scanner 42 changes the travelling direction of light (signallight LS) travelling along the optical path for OCT. Thereby, the fundusEf is scanned by the signal light LS. The galvano scanner 42 isconfigured to comprise a galvano mirror for scanning with the signallight LS in the x-direction, a galvano mirror for scanning in they-direction, and a mechanism for independently driving these. Thereby,the signal light LS may be scanned in an arbitrary direction in thexy-plane. The galvano scanner 42 is an example of “scanner”.

[OCT Unit]

An example of the configuration of the OCT unit 100 is explained whilereferring to FIG. 2. The OCT unit 100 is provided with an optical systemfor obtaining an OCT image of the fundus Ef. The optical systemcomprises a similar configuration to a conventional Spectral Domain OCTapparatus. That is to say, this optical system is configured to splitlow-coherence light into signal light and reference light, superpose thesignal light returned form the fundus Ef and the reference light havingtraveled through a reference optical path to generate interferencelight, and detect the spectral components of the interference light.This detection result (detection signal) is transmitted to thearithmetic and control unit 200.

It should be noted that when Swept Source OCT apparatus is used, a sweptsource is provided instead of a low-coherence light source while anoptical member for spectrally decomposing interference light is notprovided. In general, any known technology in accordance with the typeof OCT may be arbitrarily applied to the configuration of the OCT unit100.

A light source unit 101 outputs broadband low-coherence light L0. Thelow-coherence light L0, for example, includes near-infrared wavelengthband (about 800-900 nm) and has a coherence length of about tens ofmicrometer. Moreover, it is possible to use, as the low-coherence lightL0, near-infrared light having wavelength band that is impossible to bedetected by human eyes, for example, infrared light having the centerwavelength of about 1040-1060 nm.

The light source unit 101 is configured to comprise light output device,such as an SLD (super luminescent diode), LED, SOA (SemiconductorOptical Amplifier) and the like.

The low-coherence light L0 output from the light source unit 101 isguided to a fiber coupler 103 by an optical fiber 102 and split into thesignal light LS and the reference light LR.

The reference light LR is guided to an optical attenuator 105 by anoptical fiber 104. Through any known technology, the optical attenuator105 received control of the arithmetic and control unit 200 forautomatically adjusting light amount (light intensity) of the referencelight LR guided to the optical fiber 104. The reference light LR havingadjusted by the optical attenuator 105 is guided to a polarizationcontroller 106 by the optical fiber 104. The polarization controller 106is a device configured to, for example, apply stress to the loop-formoptical fiber 104 from outside to adjust polarization condition of thereference light LR being guided in the optical fiber 104. It should benoted that the configuration of the polarization controller 106 is notlimited to this, and arbitrary known technology may be applied. Thereference light LR having adjusted by the polarization controller 106 isguided to a fiber coupler 109.

The signal light LS generated by the fiber coupler 103 is guided by theoptical fiber 107, and converted into a parallel light flux by thecollimator lens unit 40. Further, the signal light LS travels throughthe optical path length changing part 41, the galvano scanner 42, thefocusing lens 43, the mirror 44 and the relay lens 45, and reaches thedichroic mirror 46. Further, the signal light LS is reflected by thedichroic mirror 46, refracted by the objective lens 22, and projected tothe fundus Ef. The signal light LS is scattered (including reflection)at various depth positions of the fundus Ef. The back-scattered light ofthe signal light LS from the fundus Ef travels along the same route asthe outward way in the opposite direction to the fiber coupler 103, andis reached the fiber coupler 109 through an optical fiber 108.

The fiber coupler 109 superposes the back-scattered light of the signallight LS and the reference light LR having passed through the opticalfiber 104. Interference light LC thus generated is guided by an opticalfiber 110 and output from an exit end 111. Furthermore, the interferencelight LC is converted into a parallel light flux by a collimator lens112, spectrally divided (spectrally decomposed) by a diffraction grating113, converged by a condenser lens 114, and projected onto the lightreceiving surface of a CCD image sensor 115. It should be noted thatalthough the diffraction grating 113 shown in FIG. 2 is of transmissiontype, any other kind of a spectrally decomposing element (such asreflection type) may be used.

The CCD image sensor 115 is for example a line sensor, and detects therespective spectral components of the spectrally decomposed interferencelight LC and converts the components into electric charges. The CCDimage sensor 115 accumulates these electric charges, generates adetection signal, and transmits the detection signal to the arithmeticand control unit 200.

Although a Michelson-type interferometer is employed in the presentembodiment, it is possible to employ any type of interferometer such asa Mach-Zehnder-type as necessary. Instead of a CCD image sensor, othertypes of image sensors, such as a CMOS (Complementary Metal OxideSemiconductor) image sensor, may be used.

[Arithmetic and Control Unit]

A configuration of the arithmetic and control unit 200 will bedescribed. The arithmetic and control unit 200 analyzes the detectionsignals input from the CCD image sensor 115 to form an OCT image of thefundus Ef. Arithmetic processing for this may be the same as that of aconventional Spectral Domain OCT apparatus.

Further, the arithmetic and control unit 200 controls each part of theretinal camera unit 2, the display device 3 and the OCT unit 100. Forexample, the arithmetic and control unit 200 displays an OCT image ofthe fundus Ef on the display device 3.

Further, as controls of the retinal camera unit 2, the arithmetic andcontrol unit 200 executes: controls of actions of the observation lightsource 101, the imaging light source 103 and LED's 51 and 61; control ofaction of the LCD 39; controls of movements of the focusing lenses 31and 43; control of movement of the reflection rod 67; control ofmovement of the focus optical system 60; control of movement of theoptical path length changing part 41; control of action of the galvanoscanner 42; and so on.

Further, as controls of the OCT unit 100, the arithmetic and controlunit 200 executes: control of action of the light source unit 101;control of action of the optical attenuator 105; control of action ofthe polarization controller 106; control of action of the CCD imagesensor 115; and so on.

The arithmetic and control unit 200 comprises a microprocessor, a RAM, aROM, a hard disk drive, a communication interface, and so on, as inconventional computers. The storage device such as the hard disk drivestores a computer program for controlling the fundus observationapparatus 1. The arithmetic and control unit 200 may be provided withvarious circuit boards such as a circuit board for forming OCT images.Moreover, the arithmetic and control unit 200 may be provided withoperation devices (input devices) such as a keyboard, a mouse, etc.and/or a display device such as an LCD etc.

The retinal camera unit 2, the display device 3, the OCT unit 100, andthe arithmetic and control unit 200 may be integrally configured (thatis, provided within a single case), or separately configured in two ormore cases.

[Control System]

A configuration of a control system of the fundus observation apparatus1 will be described with reference to FIGS. 3 and 4.

(Controller)

The control system of the fundus observation apparatus has aconfiguration centered on a controller 210 The controller 210 isconfigured to comprise, for example, the aforementioned microprocessor,RAM, ROM, hard disk drive, and communication interface, etc. Thecontroller 210 is provided with a main controller 211 and storage 212.

(Main Controller)

The main controller 211 performs the aforementioned various kinds ofcontrols. Specifically, the main controller 211 controls a focus driver31A, the optical path length changing part 41 and the galvano scanner 42of the retinal camera unit 2, and further controls the light source unit101, the optical attenuator 105 and the polarization controller 106 ofthe OCT unit 100.

The focus driver 31A moves the focusing lens 31 in the direction of theoptical axis. Thereby, the focus position of the imaging optical system30 is changed. It should be noted that the main controller 211 maycontrol an optical system driver (not shown in diagrams) to threedimensionally move the optical system provided in the retinal cameraunit 2. This control is used for alignment and tracking. Tracking is anoperation for move the optical system in accordance with eye movement ofthe eye E. When tracking is applied, alignment and focusing are carriedout in advance. Tracking is a function to maintain adequate positionalrelationship in which alignment and focusing are matched by causing theposition of the optical system to follow the eye movement.

The main controller 211 executes a process of writing data into thestorage 212, and a process of reading out data from the storage 212.

(Storage)

The storage 212 stores various kinds of data. The data stored in thestorage 212 may include image data of OCT images, image data of fundusimages, and eye information, for example. The eye information includesinformation on the eye, such as information on a subject such as apatient ID and a name, identification information on left eye or righteye, and so on. Further, the storage 212 stores various programs anddata for operating the fundus observation apparatus 1.

(Image Forming Part)

An image forming part 220 forms image data of a cross sectional image ofthe fundus Ef and image data of a phase image based on the detectionsignals from the CCD image sensor 115. These images will be describedlater. The image forming part 220 includes the aforementioned circuitboard and/or microprocessor, for example. It should be noted “imagedata” and the “image” based on the image data may be identified witheach other in this description. The image forming part 220 includes across sectional image forming part 221 and a phase image forming part222.

In the present embodiment, two types of scanning (a first scan andsecond scan) are performed to the fundus Ef. In the first scan, a firstcross section intersecting a blood vessel of interest (interested bloodvessel) of the fundus Ef is repeatedly scanned by the signal light LS.In the second scan, a second cross section that intersects thisinterested blood vessel and is located in the vicinity of the firstcross section is scanned by the signal light LS. Here, it is desiredthat the first and second cross sections are oriented so as to beperpendicular to the running direction the interested blood vessel. Asshown in a fundus image D of FIG. 5, in this embodiment, one first crosssection C0 and two second cross sections C1 and C2 are set in thevicinity of the optic papilla Da of the fundus Ef so as to intersect apredetermined interested blood vessel Db. One of the two second crosssections C1 and C2 is located in the upstream of the interested bloodvessel Db than the first blood vessel C0, and the other is located inthe downstream.

It should be noted that the first scan is preferably carried out duringa period of at least one cardiac cycle of the heart of the patient.Therefore, blood flow information can be obtained for all time phases ofthe heart. It should be noted that period of time in which the firstscan is performed may be a preset constant period, or may be set forevery patient or every examination. In the former case, the period oftime longer than a typical cardiac cycle may be set (for example, 2seconds). In the latter case, examination data such as anelectro-cardiogram of the patient may be referred to. Here, a factorother than cardiac cycle may be considered. Examples of such factorsinclude examination time (burden to patients), response time of thegalvano scanner 42 (scanning intervals), response time of CCD 115(scanning intervals), and so on.

(Cross Sectional Image Forming Part)

The cross sectional image forming part 221 forms cross sectional images(first cross sectional image) expressing chronological variation ofmorphology of the first cross section based on detection results of theinterference light LC acquired by the first scan. This processing willbe described in more detail. The first scan is carried out by repeatedlyscanning the first cross section C0 as described above. Detectionsignals are successively input from the CCD 115 of the OCT unit 100 intothe cross sectional image forming part 221 during the first scan. Thecross sectional image forming part 221 forms a single cross sectionalimage of the first cross section C0 based on detection signalscorresponding to the respective scans in the first scan. The crosssectional image forming part 221 repeats such processing presetrepetition times of the first scan, thereby forming a series of crosssectional images along time series. Here, it may be configured toimprove image quality by dividing these cross sectional images intomultiple groups and superposing cross sectional images in the respectivegroups.

Further, the cross sectional image forming part 221 forms a crosssectional image (second cross sectional image) expressing morphology ofthe second cross section C1 and a cross sectional image (second crosssectional image) expressing morphology of the second cross section C2based on detection results of the interference light LC acquired by thesecond scan of the second cross sections C1 and C2. This processing iscarried out in the same way as the case of the first cross sectionalimage. It should be noted that the first cross sectional image is aseries of cross sectional images in chronological order; however, thesecond cross sectional image may be a single cross sectional image.Alternatively, it may be configured to improve image quality of thesecond cross sectional images of the second cross sections C1 and C2 bysuperposing multiple cross sectional images obtained from multiplescanning of the second cross section C1 or C2.

Such processing of forming cross sectional images includes processessuch as noise elimination (noise reduction), filtering and FFT (FastFourier Transform). In the case in which other type of OCT is applied,the cross sectional image forming part 221 executes known process inaccordance with the applied OCT type.

(Phase Image Forming Part)

The phase image forming part 222 forms a phase image expressingchronological variation of phase difference in the first cross sectionbased on the detection results of the interference light LC acquired bythe first scan. The detection results used in this processing is thesame as those used in the processing of forming the first crosssectional image executed by the cross sectional image forming part 221.Therefore, position matching between the first cross sectional image andthe phase image is possible. More specifically, it is possible to obtainnatural correspondence between pixels of the first cross sectional imageand pixels of the phase image.

An example of method of forming a phase image is described. A phaseimage of the present example is obtained by calculating phase differencebetween adjacent A-line complex signals (that is, signals correspondingto adjacent scanning points). In other words, a phase image of thepresent example is formed, for each pixel of the first cross sectionalimage, based on chronological variation of pixel value (brightnessvalue) of the concerned pixel. For an arbitrary pixel, the phase imageforming part 222 considers a graph showing chronological variation ofbrightness value thereof. The phase image forming part 222 calculatesphase difference Δφ between two points of time t1 and t2 (=t1+Δt) thatare apart from each other by a preset time interval Δt in this graph.Then, this phase difference Δφ is defined as phase difference Δφ(t1) atthe point of time t1 (more generally, at an arbitrary point of timebetween the two points of time t1 and t2). Such processing is carriedout for each of many points of time that are preset, thereby obtainingthe chronological variation of phase difference at the concerned pixel.

A phase image expresses value of respective pixels at respective pointsof time as an image. This imaging processing may be realized byrepresenting values of phase difference by display colors and/orbrightness. Here, it may be configured to differentiate display color inthe case in which phase increases along time series from display colorin the case in which phase decreases (for example, the former displaycolor is red and the latter is blue). Further, the magnitude of phasevariation may be represented by color strength (color depth).Introduction of such representation methods makes it possible to clearlyindicate direction and/or speed of blood flow by display colors. A phaseimage is formed by carrying out the above processing for respectivepixels.

It should be noted that chronological variation of phase difference isobtained by assuring phase correlation by making the above time intervalΔt sufficiently small. Here, oversampling is executed under a conditionin which the time interval Δt is set to be a value smaller than the timecorresponding to the resolution of a cross sectional image in thescanning of the signal light LS.

(Image Processor)

An image processor 230 executes various image processing and analysisprocessing on images formed by the image forming part 220. For example,the image processor 230 executes various correction processing such asbrightness correction, dispersion correction of images, etc. Further,the image processor 230 executes various image processing and analysisprocessing on images obtained by the retinal camera unit 2 (fundusimages, anterior eye part images, etc.).

The image processor 230 executes known image processing such asinterpolation processing for interpolating pixels between crosssectional images to form image data of a three-dimensional image of thefundus Ef. It should be noted that the image data of a three-dimensionalimage refers to image data that the positions of pixels are defined bythe three-dimensional coordinates. The image data of a three-dimensionalimage is, for example, image data composed of three-dimensionallyarranged voxels. This image data is referred to as volume data, voxeldata, or the like. For displaying an image based on the volume data, theimage processor 230 executes a rendering process on this volume data,and forms image data of a pseudo three-dimensional image taken from aspecific view direction. On a display device such as a display 240A,this pseudo three-dimensional image is displayed.

Further, it is also possible to form stack data of multiple crosssectional images as the image data of a three-dimensional image. Stackdata is image data obtained by three-dimensionally arranging multiplecross sectional images obtained along multiple scanning lines, based onthe positional relation of the scanning lines. That is to say, stackdata is image data obtained by expressing multiple cross sectionalimages defined by originally individual two-dimensional coordinatesystems by a three-dimensional coordinate system (in other words,embedding into a three-dimensional space).

The image processor 230 includes a blood vessel region specifying part231 and a blood flow information generating part 232. The blood flowinformation generating part 232 is provided with a gradient calculatingpart 233, a blood flow velocity calculating part 234, a blood vesseldiameter calculating part 235 and a blood flow amount calculating part236. Further, the image processor 230 includes a cross section settingpart 237. These parts 231 to 237 will be described below.

(Blood Vessel Region Specifying Part)

The blood vessel region specifying part 231 specifies a blood vesselregion corresponding to the interested blood vessel Db for each of thefirst cross sectional image, the second cross sectional image and thephase image. This processing may be carried out by analyzing pixelvalues of the respective images (for example, threshold processing).

There are cases in which a phase image does not have enough resolutionfor specifying a boundary of a blood vessel region although first andsecond cross sectional images have enough resolution for executinganalysis processing. However, it is necessary to specify a blood vesselregion of a phase image with high precision and high accuracy becauseblood flow information is generated based on the phase image.Accordingly, it is desirable to specify a blood vessel region of a phaseimage more accurately by performing the following processing, forexample.

As described above, a first cross sectional image and phase image areformed from the same detection signals, correspondence between theseimages can be obtained. Utilizing this fact, firstly, a first crosssectional image is analyzed to find a blood vessel region, and then animage region in a phase image consisting of pixels corresponding to thepixels included in this blood vessel region is defined as a blood vesselregion in the phase image. This processing allows highly precise andhighly accurate specification of blood vessel regions in the phaseimage.

(Blood Flow Information Generating Part)

The blood flow information generating part 232 generates blood flowinformation related to the interested blood vessel Db based on distancebetween the first cross section and the second cross section, result ofspecification of blood vessel regions and chronological variation ofphase difference within a blood vessel region of a phase image. Here,the distance between the first cross section and the second crosssection (distance between cross sections) is determined in advance. Anexample of this will be described later in the explanation of the crosssection setting part 237. A blood vessel region is obtained by the bloodvessel region specifying part 231. The chronological variation of phasedifference within a blood vessel region of a phase image is obtained aschronological variation of phase difference at pixels within a bloodvessel region of a phase image. The following is description of anexample of configuration for performing this processing. As describedabove, the blood flow information generating part 232 is provided with agradient calculating part 233, a blood flow velocity calculating part234, a blood vessel diameter calculating part 235 and a blood flowamount calculating part 236.

(Gradient Calculating Part)

The gradient calculating part 233 calculates gradient of the interestedblood vessel Db in the first cross section based on the distance betweencross sections and the specification result of blood vessel regions. Tobegin with, the reason why the gradient of the interested blood vesselDb is calculated is explained. Blood flow information is obtained bymeans of Doppler OCT (see Patent Documents 8 and 9). A component ofvelocity of blood flow that contributes to Doppler shift is a componentin the irradiation direction of the signal light LS. Therefore, even ifblood flow velocity is the same, Doppler shift given to the signal lightLS varies in accordance with the angle between blood flow direction(that is, direction of the interested blood vessel Db) and the signallight LS, thereby changing blood flow information obtained. In order toavoid such inconvenience, it is necessary to find the gradient of theinterested blood vessel Db and reflect it in calculation processing.

Methods of calculating the gradient of the interested blood vessel Dbwill be described by referring to FIG. 6. Symbols G0, G1 and G2 indicatea first cross sectional image at the first cross section C0, a secondcross sectional image at the second cross section C1 and a second crosssectional image at the second cross section C2, respectively. Further,Symbols V0, V1 and V2 indicate a blood vessel region in the first crosssectional image G0, a blood vessel region in the second cross sectionalimage G1 and a blood vessel region in the second cross sectional imageG2, respectively. In FIG. 6, z-coordinate axis is oriented downward onthe paper surface and substantially coincides with the irradiationdirection of the signal light LS. Further, the interval between adjacentcross sectional images is denoted by “d”.

The gradient calculating part 233 calculate the gradient A of theinterested blood vessel Db at the first cross section C0 based on thepositional relationship among three blood vessel regions V0, V1 and V2.This positional relationship may be obtained, for example, by connectingthe three blood vessel regions V0, V1 and V2. More specifically, thegradient calculating part 233 identifies characteristic position in therespective three blood vessel regions V0, V1 and V2, and connects thesecharacteristic positions. Examples of this characteristic positioninclude central position, center of gravity position, uppermost part(position at which z-coordinate value is minimum), lowermost part(position at which z-coordinate value is maximum), etc. Further,examples of methods of connecting these characteristic positions includeconnection by a line segment, connection by an approximation curve(spline curve, Bezier curve, etc.), and so on.

Further, the gradient calculating part 233 calculate the gradient Abased on a (straight or curved) line connecting these characteristicpositions. When connected by a line segment, the gradient A iscalculated, for example, based on: a first line segment that connectsthe characteristic position in the first cross section C0 and thecharacteristic position in the second cross section C1; and a secondline segment that connects the characteristic position in the secondcross section C1 and the characteristic position in the second crosssection C2. As an example of this calculation, the mean value of thegradients of the two line segments may be derived. Moreover, as anexample of the case in which connection by an approximation curve, thegradient (slope) of the approximation curve at the crossing position ofthe approximation curve and the first cross section C0 may be derived.It should be noted that the distance between cross sections d is usedfor embedding the cross sectional images G0 to G2 into thexyz-coordinate system in the processing of finding a line segment or anapproximation curve.

Blood vessel regions in three cross sections are considered in thepresent example; however, it is possible to employ a configuration inwhich a gradient is calculated by considering two cross sections. As aspecific example of this, the gradient of the first or second linesegment described above may be used as the gradient to be obtained.Moreover, a single value of gradient is obtained in the present example;however, it is possible to calculate gradient for each of two or morepoints (or regions) within the blood vessel region V0. In this case, theobtained two or more values of gradient may be used separately, or thesevalues of gradient may be used to calculate the gradient A bystatistically deriving a single value (such as mean value).

(Blood Flow Velocity Calculating Part)

The blood flow velocity calculating part 234 calculates blood flowvelocity of the blood that flows within the interested blood vessel Dbat the first cross section C0 based on chronological variation of phasedifference that is obtained as a phase image. This calculated value maybe blood flow velocity at a certain point of time, or may bechronological variation of blood flow velocity (blood flow velocityvariation information). In the former case, it is possible toselectively acquire blood flow velocity at a preset time phase ofelectro-cardiogram (such as time phase of R wave), for example. Further,in the latter case, time range is the whole or arbitrary part ofscanning period of the first cross section C0.

When the blood flow velocity variation information is obtained, theblood flow velocity calculating part 234 calculates a statistic of bloodflow velocity in the concerned time range. Examples of this statisticinclude mean value, standard deviation, variance, median, maximum,minimum, local maximum, local minimum, etc. Further, histograms may becreated for values of blood flow velocity.

The blood flow velocity calculating part 234 calculates blood flowvelocity by means of Doppler OCT as described above. In this processing,the gradient A of the interested blood vessel Db at the first crosssection C0 calculated by the gradient calculating part 233 isconsidered. Specifically, the gradient calculating part 233 utilizes thefollowing relation.

$\begin{matrix}{{\Delta f} = \frac{2{nv}\;\cos\;\theta}{\lambda}} & \left\lbrack {{Formula}\mspace{14mu} 1} \right\rbrack\end{matrix}$

Here:

-   -   Δf indicates Doppler shift given to scattered light of the        signal light LS;    -   n indicates refractive index of medium;    -   v indicates flow velocity of medium (blood flow velocity);    -   θ indicates angle between irradiation direction of the signal        light LS and flow vector of medium; and    -   λ indicates center wavelength of the signal light LS.

In the present embodiment, n and λ are known, Δf is obtained fromchronological variation of phase difference, and θ is obtained from thegradient A (alternatively, θ is obtained as the gradient A). The bloodflow velocity v is calculated by substituting these values into theabove formula.

(Blood Vessel Diameter Calculating Part)

The blood vessel diameter calculating part 235 calculates the diameterof the interested blood vessel Db at the first cross section C0.Examples of this calculation include a first method of calculationutilizing a fundus image and a second method of calculation utilizing across sectional image.

In the case in which the first method of calculation is applied, imagingof a site of the fundus Ef including the location of the first crosssection C0 is carried out in advance. A fundus image thus obtained maybe an observation image (frame thereof), or may be a photographed image.When the photographed image is a color image, an image composing thephotographed image (for example, a red-free image) may be used.

The blood vessel diameter calculating part 235 sets a scale in thefundus image based on a factor(s) that determines the relationshipbetween the scale on the fundus image and the scale in the real spacesuch as photographing angle of view (photographing magnification),working distance, information about eyeball optical system. This scalerepresents length in the real space. As a specific example, this scaleassociates interval between adjacent pixels with the scale in the realspace (for example, interval of pixels=10 μm). It should be noted thatit is possible to previously calculate the relationship between variousvalues of the above factor(s) and the scale in the real space, and storeinformation that represents this relationship in the form of table orgraph. In this case, a scale corresponding to the above factor(s) isselectively applied by the blood vessel diameter calculating part 235.

Further, the blood vessel diameter calculating part 235 calculates thediameter of the interested blood vessel Db at the first cross sectionC0, that is, the diameter of the blood vessel region V0 based on thisscale and the pixels included in the blood vessel region V0. As aspecific example, the blood vessel diameter calculating part 235calculates the maximum or mean value of diameters of the blood vesselregion V0 in various directions. Further, the blood vessel diametercalculating part 235 may approximate the contour of the blood vesselregion V0 by a circle or an ellipse, and find the diameter of the circleor the ellipse. It should be noted that because determination of bloodvessel diameter allows (substantial) determination of area of the bloodvessel region V0 (that is, allows creation of (substantial) one-to-onecorrespondence between diameter and area), the area may be calculatedinstead of blood vessel diameter.

The second method of calculation is described. In the second method ofcalculation, a cross sectional image of the fundus Ef at the first crosssection C0 is utilized. This cross sectional image may be the firstcross sectional image or may be one obtained separately from the firstcross sectional image.

A scale in this cross sectional image is determined in accordance withscanning mode of the signal light LS. In the present embodiment, thefirst cross section C0 is scanned as illustrated in FIG. 5. The lengthof this first cross section is determined based on various factors thatdetermine the relationship between the scale on an image and the scalein the real space such as working distance, information about eyeballoptical system. The blood vessel diameter calculating part 235, forexample, finds the interval between adjacent pixels based on thislength, and calculates the diameter of the interested blood vessel Db atthe first cross section C0 in the similar fashion to the first method ofcalculation.

(Blood Flow Amount Calculating Part)

The blood flow amount calculating part 236 calculates flow amount (flowrate) of blood that flows within the interested blood vessel based oncalculation result of blood flow velocity and calculation result ofblood vessel diameter. The following is an example of this processing.

It is assumed that blood flow in blood vessel is Hagen-Poiseuille flow).Further, for blood vessel diameter w and maximum of blood flow velocityVm, blood flow amount Q is expressed as in the following formula.

$\begin{matrix}{Q = {\frac{\pi\; w^{2}}{8}{Vm}}} & \left\lbrack {{Formula}\mspace{14mu} 2} \right\rbrack\end{matrix}$

The objective blood flow amount Q is calculated by substituting theresult w of blood vessel diameter calculated by the blood vesseldiameter calculating part 235 and the maximum Vm based on the blood flowvelocity calculated by the blood flow velocity calculating part 234 intothis formula.

(Cross Section Setting Part)

The main controller 211 displays a fundus image on the display 240A. Thefundus image may be an observation image or a photographed image.Alternatively, the fundus image may be an image included in aphotographed image. The user operates the operation part 240B todesignate the first cross section C0 on the fundus image displayed. Thecross section setting part 237 sets the second cross sections C1 and C2based on the designated first cross section C0 and the fundus image. Itshould be noted that the first cross section C0 is designated so as tocross a desired interested blood vessel Db, as described above.

An operation for designating the first cross section C0 on the fundusimage is carried out by means of a pointing device, for example.Further, when the display 240A is a touch panel, the user designates thefirst cross section C0 by touching a desired location in the fundusimage displayed. In this case, a parameter(s) (orientation, length,etc.) of the first cross section C0 is set manually or automatically.

As an example of manual setting, the user may use an interface forsetting the parameter. This interface may be hardware such as a switch,or may be software such as a graphical user interface (GUI).

As an example of automatic setting, the cross section setting part 237sets the parameter based on the location designated on the fundus imageby the user. In automatic setting of length, a preset value may beapplied, or the designated location and location of blood vessel in thevicinity of the designated location may be taken into account. Theformer value is designated based on a typical distance between thedesired interested blood vessel and a blood vessel in the vicinitythereof, for example. Information on this distance may be generatedbased on clinical data. The latter case may be similarly carried out. Inany case, the length of the first cross section C0 may be set so as tocross the interested blood vessel Db and cross no other blood vessels(in particular, thick blood vessels).

In automatic setting of orientation of the first cross section C0, apreset orientation may be applied or the orientation of the interestedblood vessel Db may be taken into account. In the farmer case,information expressing gradient of an interested blood vessel atrespective locations thereof may be generated and this information isreferred to. This information may be generated based on clinical data.In the latter case, the running direction of the interested blood vesselDb at the designated location is found and the orientation of the firstcross section C0 is set based on this running direction. The processingof finding the running direction is carried out by applying thinningprocessing to the interested blood vessel Db, for example. It should benoted that in any case, the orientation of the first cross section C0 ispreferably set so as to orthogonally cross the running direction.

Next, processing of setting the second cross sections C1 and C2 isdescribed. The cross section setting part 237 sets the second crosssections C1 and C2 at the locations preset distance away from the firstcross section C0. This distance is set to 100 μm, for example.Specification of this distance is carried out in the aforementioned way,for example. Further, lengths and/or orientations of the second crosssections C1 and C2 may be set in the same way as in the case of thefirst cross section C0.

It should be noted that in the present embodiment, cross sections C0, C1and C2 (that is, scanning positions of the signal light LS) are setbased on a fundus image. To do so, it is necessary to obtaincorrespondence between the fundus image and scanning positions. In orderto obtain this correspondence, it is preferable that, as in the presentembodiment, the optical system for fundus photography and optical systemfor OCT measurement share part of optical path of each other. Byapplying such a coaxial configuration, positions in the fundus image andscanning positions may be associated with each other by considering thisoptical axis as a reference. Here, in this correspondence, displaymagnification of the fundus image (including at least one of so-calledoptical zooming and digital zooming) may be taken into account.

In the case in which such coaxial configuration is not applied, a fundusimage and scanning positions are associated with each other based on thefundus image and a projection image obtained by OCT measurement. Itshould be noted that the projection image is an image that expressesmorphology of fundus surface and is obtained by adding up, in the depthdirection (z-direction), a three-dimensional image that is acquired bythree-dimensional scan described later. By using such a projectionimage, positions in the fundus image and positions in the projectionimage may be associated with each other by means of image correlation,for example, and this association may give association between thefundus image and the scanning positions. It should be noted that whentaking influences of eye movement of the eye E (involuntary eye movementduring fixation etc.) into account, it can be said that the coaxialconfiguration is more preferable since both imaging modalities may beperformed with substantially no time lag.

The image processor 230 that functions as above comprises, for example,the aforementioned microprocessor, RAM, ROM, hard disk drive, circuitboard, and so on. A computer program that causes the microprocessor toperform the above functions is stored in the storage device such as thehard disk drive in advance.

(User Interface)

A user interface 240 comprises the display 240A and the operation part240B. The display 240A is configured to include a display device of theaforementioned arithmetic and control unit 200 and/or the display device3. The operation part 240B is configured to include an operation deviceof the aforementioned arithmetic and control unit 200. The operationpart 240B may also comprise various kinds of buttons, keys, etc. thatare provided with the case of the fundus observation apparatus 1 oroutside thereof. For example, when the retinal camera unit 2 has a casethat is similar to conventional retinal cameras, a joy stick, operationpanel, etc. provided with the case may also be included in the operationpart 240B. Furthermore, the display 240A may also include variousdisplay devices such as a touch panel monitor etc. provided with thecase of the retinal camera unit 2.

The display 240A and the operation part 240B do not need to beconfigured as separate components. For example, like a touch panel, itis possible to apply a device in which the display function and theoperation function are integrated. In this case, the operation part 240Bis configured to include a touch panel and a computer program. A contentof operation to the operation part 240B is input into the controller 210as an electrical signal. Further, operations and/or information inputmay be carried out by using a GUI displayed on the display 240A and theoperation part 240B.

[Scanning with Signal Light and OCT Images]

Here, scanning with the signal light LS and OCT image are explained.

The scanning modes of the signal light LS by the fundus observationapparatus 1 may include, for example, horizontal scan, vertical scan,cruciform scan, radial scan, circular scan, concentric scan, helicalscan, etc. These scanning modes are selectively used as necessary takinginto account an observation site of a fundus, an analysis target(retinal thickness etc.), time required for scanning, the density ofscanning, and so on.

The horizontal scan is one for scanning the signal light LS in thehorizontal direction (x-direction). The horizontal scan includes a modeof scanning the signal light LS along multiple scanning lines extendingin the horizontal direction arranged in the vertical direction(y-direction). In this mode, the interval of scanning lines may bearbitrarily set. Further, by setting the interval between adjacentscanning lines to be sufficiently narrow, it is possible to form theaforementioned three-dimensional image (three-dimensional scan). Thevertical scan is performed in a similar manner.

The cruciform scan is one for scanning the signal light LS along across-shape trajectory consisting of two linear trajectories (linetrajectories) orthogonal to each other. The radial scan is one forscanning the signal light LS along a radial trajectory consisting ofmultiple line trajectories arranged at predetermined angles. It shouldbe noted that the cruciform scan is an example of the radial scan.

The circular scan is one for scanning the signal light LS along acircular trajectory. The concentric scan is one for scanning the signallight LS along multiple circular trajectories arranged concentricallyaround a predetermined center position. The circular scan is an exampleof the concentric scan. The helical scan is one for scanning the signallight LS along a helical trajectory while making the turning radiusgradually smaller (or greater).

Since the galvano scanner 42 is configured to scan the signal light LSin the directions orthogonal to each other, the galvano scanner 42 iscapable of scanning the signal light LS in the x-direction and they-direction independently. Moreover, it is possible to scan the signallight LS along an arbitrary trajectory on the xy-plane by simultaneouslycontrolling the directions of two galvano mirrors included in thegalvano mirror 42. Thus, various kinds of scanning modes as describedabove may be realized.

By scanning the signal light LS in the modes described above, it ispossible to obtain a cross sectional image in the plane spanned by thedirection along the scanning line and the depth direction (z-direction)of the fundus. Moreover, in a case in which the interval betweenscanning lines is narrow, it is possible to obtain the aforementionedthree-dimensional image.

A region on the fundus Ef subjected to scanning by the signal light LSas above, that is, a region on the fundus Ef subjected to OCTmeasurement, is referred to as a scanning region. A scanning region forthe three-dimensional scan is a rectangular-shaped region in whichmultiple horizontal scans are arranged. Furthermore, a scanning regionfor the concentric circular scan is a disc-shaped region surrounded bythe trajectories of a circular scan of a maximum diameter. Moreover, thescanning region for the radial scan is a disc-shaped (orpolygonal-shaped) region linking end positions of the scanning lines.

[Operation]

An operation of the fundus observation apparatus 1 is described. FIG. 7illustrates an example of the operation of the fundus observationapparatus 1.

(S1: Preparation for Measurement)

As preparation for OCT measurement, input of a patient ID, selection ofoperation mode corresponding to the present embodiment (blood flowmeasurement mode), etc. are carried out.

(S2: Alignment and Focusing)

Next, near-infrared moving image (observation image) of the fundus Ef isacquired by continuously illuminating the fundus Ef with illuminationlight from the observation light source 11. The main controller 211displays this observation light on the display 240A.

At this time, the fixation target from the LCD 39, the alignment targetfrom the alignment optical system 50 and the split target from the focusoptical system 60 are projected onto the eye E. Thereby, the alignmenttarget and split target are depicted in the observation image displayed.Alignment and focusing are carried out using these targets. It should benoted that the fixation target for observing an optic papilla is appliedin the present embodiment. Here, tracking in which an optical papilla isa target may be started.

(S3: Designation of Measurement Location)

Subsequently, the user designates measurement location of blood flowonto the fundus image displayed. The location designated here is a firstcross section. It should be noted that this fundus image may be anobservation image or photographed image (or an image included in this).The methods of designating the first cross section are described above.

(S4: Setting of Cross Section in the Vicinity of Measurement Location)

Once the first cross section is designated, the cross section settingpart 237 sets a second cross section(s) based on the first crosssection.

(S5: Verification of OCT Image)

The main controller 211 controls the light source unit 101, the galvanoscanner 42, etc. to carry out OCT measurement. This OCT measurement isperformed for the first cross section, the second cross sections, or across section other than these. Verification whether a suitable OCTimage is acquired is performed by referring to this OCT image. Thisverification may be carried out by visual observation or may beautomatically carried out by the fundus observation apparatus 1.

When carried out by visual observation, the main controller 211 displaysthis OCT image on the display 240A. The user evaluates positiondisplayed on the frame, image quality of the OCT image, and so on, andinputs the result of the verification using the operation part 240B.When a suitable image is not acquired, adjustment of measurementconditions is carried out. When the displayed position of the image isnot suitable, the optical length of the signal light LS is changed bythe optical path length changing part 41. Further, when the imagequality is not suitable, the optical attenuator 105 and/or thepolarization controller 106 are/is adjusted.

In the case of automatic execution, the displayed position, imagequality, etc. are evaluated with referring to a preset evaluationstandard, and measurement conditions are adjusted based on theevaluation result in the same fashion as in the case of manualexecution.

(S6: Commencement of Blood Flow Measurement)

Blood flow measurement is started in response to a predeterminedtrigger.

(S7: Execution of OCT Measurement)

The blood flow measurement is begun with OCT measurement for the firstcross section and the second cross sections to form a first crosssectional image, a second cross sectional image and a phase image.

(S8: Specification of Blood Vessel Regions)

The blood vessel region specifying part 231 specifies a blood vesselregion from each of the first cross sectional image, the second crosssectional image and the phase image.

(S9: Calculation of Gradient of Interested Blood Vessel)

The gradient calculating part 233 calculates the gradient of theinterested blood vessel at the first cross section based on the distancebetween cross sections and the specification result of the blood vesselregion.

(S10: Calculation of Blood Flow Velocity)

The blood flow velocity calculating part 234 calculates blood flowvelocity of the blood that flows within the interested blood vessel atthe first cross section based on chronological variation of phasedifference that is obtained as the phase image and the gradient of theinterested blood vessel.

(S11: Calculation of Blood Vessel Diameter)

The blood vessel diameter calculating part 235 calculates the diameterof the interested blood vessel at the first cross section based on afundus image or a cross sectional image (the first cross sectional imageetc.).

(S12: Calculation of Blood Flow Amount)

The blood flow amount calculating part 236 calculates flow amount ofblood that flows within the interested blood vessel based on calculationresult of blood flow velocity and the calculation result of blood vesseldiameter.

(S13: Display and Storage of Measurement Result)

The main controller 211 displays blood flow information including thecalculation result of blood flow velocity, the calculation result ofblood flow amount, etc. on the display 240A. Further, the maincontroller 211 associates the blood flow information with the patient IDand stores it in the storage 212. This is the end of the processingrelated to the blood flow measurement of the present embodiment.

[Effects]

Effects of the fundus observation apparatus 1 are explained.

The fundus observation apparatus 1 includes the optical system for OCTmeasurement, the galvano scanner 42, the image forming part 220, theblood vessel region specifying part 231 and the blood flow informationgenerating part 232.

The optical system for OCT measurement splits light from the lightsource unit 101 into the signal light LS and the reference light LR, anddetects the interference light LC between scattered light of the signallight LS from the fundus Ef and the reference light LR having traveledby way of the reference optical path.

The galvano scanner 42 carries out a first scan. In the first scan, afirst cross section that crosses an interested blood vessel in thefundus Ef is repeatedly scanned with the signal light LS.

The image forming part 220 forms a first cross sectional image and aphase image. The first cross sectional image expresses chronologicalvariation of morphology of the first cross section and is formed basedon detection results of the interference light LC acquired by theoptical system during the first scan. The phase image expresseschronological variation of phase difference of the first cross sectionand is formed based on detection results of the interference light LCacquired by the optical system during the first scan.

The blood vessel region specifying part 231 specifies a blood vesselregion corresponding to the interested blood vessel for each of thefirst cross sectional image and the phase image.

The blood flow information generating part 232 generates blood flowinformation related to the interested blood vessel based on the bloodvessel region of the first cross sectional image and the chronologicalvariation of phase difference within the blood vessel region of thephase image. This is a basic action of the present embodiment.

The galvano scanner 42 may be configured to carry out a second scan inaddition to the first scan. In the second scan, a second cross sectionis scanned with the signal light LS, wherein the second cross sectioncrosses the interested blood vessel and is located in the vicinity ofthe first cross section. In this case, the image forming part 220 formsa second cross sectional image in addition to the first cross sectionalimage and the phase image, the second cross sectional image expressesmorphology of the second cross section and is formed based on thedetection results of the interference light LC acquired by the opticalsystem during the second scan. Further, the blood vessel regionspecifying part 231 carries out specification of a blood vessel regioncorresponding to the interested blood vessel in the second crosssectional image as well. The blood flow information generating part 232generates the blood flow information based on the distance between thefirst cross section and the second cross section, the blood vesselregion of the first cross sectional image, the blood vessel region ofthe second cross sectional image, and the chronological variation ofphase difference expressed by the phase image.

The blood flow information generating part 232 may be configured asfollows: (1) the blood flow information generating part 232 includes thegradient calculating part 233 that is configured to calculate gradientof the interested blood vessel at the first cross section based on thedistance between the first cross section and the second cross section,the blood vessel region of the first cross sectional image and the bloodvessel region of the second cross sectional image; (2) the blood flowinformation generating part 232 generates the blood flow informationbased on calculation result of the gradient and the chronologicalvariation of phase difference.

The second cross section may include a cross section located in theupstream of the interested blood vessel from the first cross section anda cross section located in the downstream.

The gradient calculating part 233 may be configured to calculate thegradient of the interested blood vessel at the first cross section basedon location of the blood vessel region of the first cross sectionalimage and location of the blood vessel region of the second crosssectional image.

The blood flow information generating part may include the blood flowvelocity calculating part 234 that is configured to calculate blood flowvelocity of the blood that flows within the interested blood vessel atthe first cross section based on calculation result of the gradient ofthe interested blood vessel obtained by the gradient calculating part233 and the chronological variation of phase difference.

The blood flow velocity calculating part 234 may be configured togenerate blood flow velocity variation information that expresseschronological variation of the blood flow velocity based on thechronological variation of phase difference.

The blood flow velocity calculating part 234 may be configured tocalculate a statistic of the blood flow velocity based on the blood flowvelocity variation information.

The fundus camera unit 2 photographs a site of the fundus Ef includingthe location of the first cross section. In this case, the blood vesseldiameter calculating part 235 and the blood flow amount calculating part236 in the blood flow information generating part 232 function asfollows. The blood vessel diameter calculating part 235 calculatesdiameter of the interested blood vessel at the first cross section basedon the image photographed by the retinal camera unit 2. Further, theblood flow amount calculating part 236 calculates amount of blood flowwithin the interested blood vessel based on the blood flow velocityvariation information and the calculation result of the diameter.

Instead of this, it may be configured that the blood vessel diametercalculating part 235 calculates diameter of the interested blood vesselat the first cross section based on the first cross sectional image andthe blood flow amount calculating part 236 calculates amount of bloodflow within the interested blood vessel based on the blood flow velocityvariation information and the calculation result of the diameter.

The blood vessel region specifying part 231 may be configured to analyzethe first cross sectional image to specify blood vessel region, specifyimage region of the phase image corresponding to the location of thisblood vessel region of the first cross sectional image, and set thisspecified image region as blood vessel region of the phase image.

It may be configured that the first scan may be carried out over atleast one cardiac cycle of the patient. In particular, when the above[Formula 2] is applied in the calculation of the blood flow amount, themaximum of the blood flow velocity in one cardiac cycle may be used.

The first cross section and the second cross section may be set in thevicinity of the optic papilla of the fundus. In conventional blood flowmeasurement using laser Doppler, an interested blood vessel is measuredat location that is apart from an optic papilla by the optic papilladiameter (or distance more than this) according to the characteristic ofthe method. However, when OCT is used as the present embodiment,measurement may be carried out at closer locations to the optic papilla.Accordingly, it is considered to improve accuracy and precision of themeasurement.

According to the fundus observation apparatus 1 of the presentembodiment thus configured, it is possible to realize blood flowmeasurement with high accuracy because it is configured to carry outblood flow measurement using the first cross sectional image at the samecross section as the phase image and chronological variation of phasedifference.

Further, the fundus observation apparatus 1 may have the followingcharacteristics. Namely, the fundus observation apparatus 1 includes theoptical system for OCT measurement, the galvano scanner 42, the imageforming part 220, the retinal camera unit 2, the blood vessel regionspecifying part 231, the blood flow velocity calculating part 234, theblood vessel diameter calculating part 235 and the blood flow amountcalculating part 236.

The optical system for OCT measurement splits light from the lightsource unit 101 into the signal light LS and the reference light LR, anddetects the interference light LC between scattered light of the signallight LS from the fundus Ef and the reference light LR having traveledby way of the reference optical path.

The galvano scanner 42 carries out a first scan and a second scan. Inthe first scan, a first cross section that crosses an interested bloodvessel in the fundus Ef is repeatedly scanned with the signal light LS.In the second scan, a second cross section is scanned with the signallight LS, wherein the second cross section crosses the interested bloodvessel and is located in the vicinity of the first cross section.

The image forming part 220 forms a first cross sectional image, a phaseimage and a second cross sectional image. The first cross sectionalimage expresses chronological variation of morphology of the first crosssection and is formed based on detection results of the interferencelight LC acquired by the optical system during the first scan. The phaseimage expresses chronological variation of phase difference of the firstcross section and is formed based on detection results of theinterference light LC acquired by the optical system during the firstscan. The second cross sectional image expresses morphology of thesecond cross section and is formed based on detection results of theinterference light LC acquired by the optical system during the secondscan.

The retinal camera unit 2 photographs a site of the fundus Ef includingthe location of the first cross section.

The blood vessel region specifying part 231 specifies a blood vesselregion corresponding to the interested blood vessel for each of thefirst cross sectional image, the phase image and the second crosssectional image.

The blood flow velocity calculating part 234 calculates blood flowvelocity of the blood that flows within the interested blood vessel atthe first cross section based on the chronological variation of phasedifference and the specification result of the blood vessel region(gradient of the interested blood vessel obtained from the blood vesselregion).

The blood vessel diameter calculating part 235 calculates diameter ofthe interested blood vessel at the first cross section based on thephotographed image of the site by the retinal camera unit 2.

The blood flow amount calculating part 236 calculates amount of bloodflow within the interested blood vessel based on calculation result ofthe blood flow velocity and the calculation result of the diameter. Thisis a basic action of the present embodiment.

It may be configured that the first scan may be carried out over atleast one cardiac cycle of the patient. In particular, when the above[Formula 2] is applied in the calculation of the blood flow amount, themaximum of the blood flow velocity in one cardiac cycle may be used.

The first cross section and the second cross section may be set in thevicinity of the optic papilla of the fundus. In conventional blood flowmeasurement using laser Doppler, an interested blood vessel is measuredat location that is apart from an optic papilla by the optic papilladiameter (or distance more than this) according to the characteristic ofthe method. However, when OCT is used as the present embodiment,measurement may be carried out at closer locations to the optic papilla.Accordingly, it is considered to improve accuracy and precision of themeasurement.

The imaging optical system 30 of the retinal camera unit 2 shares partof optical path with the optical system for OCT measurement. The display240A displays an image photographed by the retinal camera unit 2. Whenthe user designates the first cross section to the photographed imagedisplayed by means of the operation part 240B, the cross section settingpart 237 sets the second cross section based on the first cross sectiondesignated and the photographed image. The galvano scanner 42 carriesout the first scan of the first cross section designated and carries outthe second scan of the second cross section set.

According to the fundus observation apparatus 1 of the presentembodiment thus configured, blood flow measurement may be carried out byusing the first cross sectional image at the same cross section as thephase image and chronological variation of phase difference. Further,the fundus observation apparatus 1 calculates blood flow velocity basedon chronological variation of phase difference and specification resultof the blood vessel region, calculates the diameter of the interestedblood vessel based on the photographed image, and calculates the bloodflow amount based on calculation result of the blood flow velocity andcalculation result of the blood vessel diameter. Accordingly, blood flowmeasurement with high accuracy may be realized.

Examples of Modification

The configuration described above is merely illustrations for favorablyimplementing the present invention. Therefore, it is possible to makearbitrary modification (omission, replacement, addition, etc.) withinthe scope of the present invention.

A modification example of method of calculating blood flow amount isdescribed. In the present modification example, the blood flow velocitycalculating part 234 generates information (blood flow velocityvariation information) that expresses chronological variation of theblood flow velocity for each pixel included in the blood vessel regionof the phase image. This processing may include: processing ofassociating pixels of multiple phase images along time series by each ofpixel positions; and processing of generating the blood flow velocityvariation information based on the multiple pixels along time seriescorresponding to the respective pixel positions. From such processing,blood flow velocity at each position in the blood vessel region of thefirst cross section may be obtained.

The blood flow amount calculating part 236 calculates blood flow amountfor the respective pixels by time-integrating the blood flow velocityvariation information for the respective pixels included in the bloodvessel region. From this processing, blood flow amount at each point inthe blood vessel region of the first cross section is calculated.

Further, the blood flow amount calculating part 236 calculates bloodflow amount within the interested blood vessel by adding the blood flowamounts for these pixels. By this processing, blood flow amounts for themultiple pixels obtained in the prior stage are added together and thetotal amount of blood that flows within the blood vessel region of thefirst cross section.

In the above embodiment, the optical path length difference between theoptical path of the signal light LS and the optical path of thereference light LR is changed by varying the position of the opticalpath length changing part 41; however, a method for changing the opticalpath length difference is not limited to this. For example, it ispossible to change the optical path length difference by providing areference mirror (reference mirror) in the optical path of the referencelight and moving the reference mirror in the advancing direction of thereference light to change the optical path length of the referencelight. Further, the optical path length difference may be changed bymoving the retinal camera unit 2 and/or the OCT unit 100 with respect tothe eye E to change the optical path length of the signal light LS.Moreover, in a case that an object is not a living site or the like, itis also effective to change the optical path length difference by movingthe object in the depth direction (z-direction).

Computer programs for implementing the above embodiments can be storedin any kind of recording medium that can be read by a computer. As suchrecording media, for example, an optical disk, a semiconductor memory, amagneto-optic disk (CD-ROM, DVD-RAM, DVD-ROM, MO, and so on), and amagnetic storage (a hard disk, a Floppy Disk™, ZIP, and so on) can beused.

In addition, it is possible to transmit/receive this program through anetwork such as internet or LAN etc.

[Embodiments of Image Displaying Apparatus]

Embodiments of image displaying apparatus etc. are described in thefollowing with referring to diagrams. It should be noted that componentswith the same symbol carry out similar action, so repetition ofexplanation is sometimes omitted.

FIG. 8 is a block diagram of an image displaying apparatus 1000 in thepresent embodiment. The present embodiment describes an example ofprocessing of displaying a cross sectional image, phase image, bloodflow information, cross section blood vessel management information,phase blood vessel management information, etc. acquired in the aboveembodiments. For example, images and information acquired in the aboveembodiment are accumulated in cross sectional image storage 1011, phaseimage storage 1012 and blood flow information storage 1013 etc.

The image displaying apparatus 1000 is provided with cross sectionalimage storage 1011, phase image storage 1012 and blood flow informationstorage 1013, living body image storage 1014, phase blood vesselmanagement information storage 1015, cross section blood vesselmanagement information storage 1016, blood vessel management informationstorage 1017, change operation receiving part 1018, blood vesselclassification designating operation receiving part 1019, blood vesselclassification management information storage 1020, blood vesselclassification management information accumulating part 1021 and display1022.

One or more cross sectional image group is stored in the cross sectionalimage storage 1011. A cross sectional image group includes multiplecross sectional images. A cross sectional image is an image expressesinside of a living body acquired from tomographic imaging utilizing OCTor the like, for example. For example, a cross sectional image expressesa cross section at one position in the living body. One cross sectionalimage group is usually includes multiple cross sectional images acquiredfor one location. A cross sectional image included in the crosssectional image group is an image associated with time and is a crosssectional image expresses a cross section that crosses at least oneblood vessel in the living body, for example. Specifically, it is across sectional image expresses a cross section that crosses in theextending direction of the blood vessel. Specifically, the crosssectional image is an image of cross section of the living body that isformed, when the living body is repeatedly scanned with signal lightoutput from laser source, based on detection results of interferencelight between reference light obtained from the same light source as thesignal light and scattered light from the living body, and examples ofprocessing of acquiring cross sectional images are described later.

Time associated with a cross sectional image is, for example, the timeof acquisition of the cross sectional image (for example, time at whichone cross sectional image is acquired using OCT apparatus). The timehere may include information such as a date. A cross sectional imagegroup is a moving image consisting of frame images that are one or morecross sectional images associated with time, for example. In this case,time may be associated with each frame image as a time code etc. Thetime here may be an absolute time such as some hour some minute, may besequential identification information such as frame number, or may be arelative time that is counted from starting point of time at which onecross sectional image is output (for example, elapse of time from outputof one cross sectional image). Further, time may be acquisition timingor output timing of each cross sectional image, or information in whichorders of acquisition or orders of output etc. are identifiable. Thesematters are similar in the below. Further, multiple cross sectionalimages associated with time may be a file of multiple cross sectionalimages associated with time etc. For example, in this case, crosssectional images may be played as a moving image by reading out the fileof cross sectional images by each time associated. However, a crosssectional image group may be multiple cross sectional images thatindividually have no information of time arranged in order ofacquisition. In this case also, each cross sectional image is consideredto be associated with time because time associated with each crosssectional image can be obtained from information such as starting time,frame rate etc. Such matters may be similar for phase images, blood flowinformation, living body images, etc. A cross sectional image stored inthe cross sectional image storage 1011 is an image expressing a crosssection at one or more location (site) of eye fundus, cornea etc. in theliving body, for example.

Cross section management information is stored in the cross sectionalimage storage 1011, for example. The cross section managementinformation includes cross sectional image group and blood vesselidentification information that is information indicating one Or moreblood vessel intersecting the cross section expressed by this crosssectional image group. The fact that it crosses one or more blood vesselmeans that a cross section of one or more blood vessel is included inthe cross sectional image, for example. A cross section or blood vesselhere is, for example, a cross section that intersects in the directionin which one blood vessel extends. The blood vessel identificationinformation is information such as name of blood vessel, code assignedto blood vessel, one or more coordinate indicating location of bloodvessel, etc. The location of blood vessel is location of blood vessel inthe living body described later, for example. It should be noted thatthe location here may be a place or a region. In the case of region, theblood vessel identification information may be multiple coordinategroups indicating contour of this region, multiple coordinate groups ofmultiple pixels included in this region. Here, ways of defining oneblood vessel is not a problem so long as blood vessel is identifiable.For example, area partitioned by end or junction of blood vessel may beconsidered as one blood vessel, or main blood vessel and blood vesselbranched from the main blood vessel may individually be regarded as oneblood vessel.

It should be noted that storage here is a concept including temporalmemory, for example. For example, processing of temporally storing across sectional image acquired by the optical image measuring apparatus1 is also considered as storage here.

The cross sectional image storage 1011 is preferably a nonvolatilerecording medium; however, volatile recording medium may also be used.It should be noted that such matters are the same for the phase imagestorage 1012, the blood flow information storage 1013, the living bodyimage storage 1014, the phase blood vessel management informationstorage 1015, the cross section blood vessel management informationstorage 1016, the blood vessel management information storage 1017 andthe blood vessel classification management information storage 1020 etc.

One or more phase image group is stored in the phase image storage 1012.A phase image group includes multiple phase images. A phase image is animage that is associated with time and expresses chronological variationof phase difference at a cross section intersecting at least one bloodvessel in the living body. Specifically, the phase image is an imageexpressing chronological variation of phase difference at a crosssection of the living body that is formed, when the living body isrepeatedly scanned with signal light output from laser source, based ondetection results of interference light between reference light obtainedfrom the same light source as the signal light and scattered light fromthe living body. One living body image group is usually includesmultiple living body images acquired for one location. Typically,detection results of interference light used for acquisition of phaseimages at one location of the living body is the same as detectionresults of interference light used for acquisition of cross sectionalimages at the same location. Therefore, position matching is possiblebetween cross sectional images and phase images acquired at the samelocation in the same living body. That is, it is possible to give anatural correspondence between pixels of cross sectional images andpixels of phase images acquired at the same location. It should be notedthat the same location is considered as the fact that cross sectionexpressed by cross sectional image and cross section expressed by phaseimage are the same, for example. Examples of processing of acquiringphase image etc. are described later.

Time associated with a phase image is, for example, the same as the timeassociated with the cross sectional image that is formed from the samedetection results of interference light. Alternatively, it may be timeat which the phase image is acquired. A phase image group may be amoving image consisting of frame images that are one or more phaseimages associated with time, a file of multiple cross sectional imagesassociated with time, multiple cross sectional images arranged in orderof acquisition. A phase image stored in the phase image storage 1012 isa phase image of a cross section at one or more location (site) of eyefundus, cornea etc. in the living body, for example.

One or more phase management information is stored in the phase imagestorage 1012, for example. The phase management information includes,for example, phase image group and blood vessel identificationinformation of one or more blood vessel intersecting the cross sectioncorresponding to the phase image group.

It should be noted that storage here is a concept including temporalmemory, for example. For example, processing of temporally storing aphase image acquired by the optical image measuring apparatus describedlater is also considered as storage here.

One or more blood flow information group is stored in the blood flowinformation storage 1013. A blood flow information group includesmultiple blood flow information. Blood flow information is informationrelated to flow of blood in a blood vessel in the living body. One bloodflow information group is typically configured by multiple blood flowinformation acquired for one blood vessel of one location of one bloodvessel. Blood flow information is, for example, flow velocity, flowamount etc. of blood that flows in one blood vessel. Blood flowinformation is associated with time. Time associated with blood flowinformation is, for example, time at which blood flow information isacquired. Blood flow information is generated, for example, based onchronological variation of phase difference in the region in which thecross section of blood vessel in a phase image acquired for one bloodvessel. This object of calculation may be blood flow velocity at acertain point of time, or may be chronological variation of blood flowvelocity (blood flow velocity variation information). In the formercase, it is possible to selectively acquire blood flow velocity at apreset time phase of electro-cardiogram (such as time phase of R wave),for example. Further, in the latter case, time range is the whole orarbitrary part of scanning period with signal light for acquiring aphase image. When the blood flow velocity variation information isobtained, a statistic of blood flow velocity in the concerned time rangemay be calculated. Examples of this statistic include mean value,standard deviation, variance, median, maximum, minimum, local maximum,local minimum, etc. Further, histograms may be created for values ofblood flow velocity. It should be noted that blood flow informationstored in the blood flow information storage 1013 is preferably acquiredusing OCT. Details of processing of acquiring blood flow information aredescribed later. A blood vessel in the living body here is a bloodvessel in an eye fundus, cornea etc. of the living body, for example.

One or more blood flow management information is stored in the bloodflow information storage 1013, for example. The blood flow managementinformation includes, for example, blood flow information group andblood vessel identification information of blood vessel corresponding tothis blood flow information group.

It should be noted that storage here is a concept including temporalmemory, for example. For example, processing of temporally storing bloodflow information acquired by the optical image measuring apparatus 1etc. is also considered as storage here.

The living body image storage 1014 stores a living body image obtainedby photographing a living body. A living body is an image obtained byphotographing, from the front, a region including location in which across sectional image is acquired, for example. The front means frontside of a living body (such as a human body), for example. Further, thefront may be considered to be a surface onto which signal light isirradiated, wherein the signal light is scanned when performingtomographic imaging for acquiring cross sectional images etc. asdescribed above, for example. For example, a living body image may beconsidered to be an image obtained by photographing a living body towarda parallel direction to the cross section expressed by a cross sectionalimage. For example, a living body image is a fundus image such as afundus photograph obtained by photographing a fundus from a positionfacing the fundus of a living body or a cornea image obtained byphotographing a cornea from a position facing the cornea of a livingbody and so on when the abovementioned cross sectional image is an imageexpressing a fundus or cornea. A living body image is preferably animage in which a blood vessel in a living body can be recognized byvisual observation etc. A living body image is preferably an imageobtained by photographing a location in which one or more crosssectional image, phase image, blood vessel information etc. Moreover, aliving body image is preferably an image obtained by photographing aregion in which one or more blood vessel included in a cross sectionalimage, phase image etc. or blood vessel corresponding to blood vesselinformation.

Further, the living body image storage 1014 may store multiple livingbody images associated with time. For example, the living body imagestorage 1014 may store a living body image group including multipleliving body images associated with time. In this case, a living bodyimage group typically includes multiple living body images acquired forone location. This location is a concept including a region and anobject. Further, this living body image group may be a moving imagesimilar to the abovementioned cross sectional image group.

The phase blood vessel management information storage 1015 stores phaseblood vessel management information. The phase blood vessel managementinformation includes phase blood vessel location information thatexpresses location of a blood vessel in a phase image and blood vesselidentification information of this blood vessel. The phase blood vesselmanagement information may further include identification informationfor identifying a corresponding phase image. The identificationinformation of a phase image may be a code or file name etc.individually assigned to a phase image, or a combination ofidentification information for identifying the phase image group towhich the phase image belongs (for example, file name indicating thephase image group or name of directory in which phase images in thephase image group is stored when the phase image group is a movingimage) and time or frame number etc. associated with the respectivephase images. However, the identification information of a phase imagemay be any kind of information as long as phase images are identifiable.

It may be configured to utilize phase blood vessel location informationset to one phase image in one phase image group as phase blood vessellocation information of other phase images in the same phase imagegroup. In other words, common phase blood vessel location informationmay be set for the respective phase images in one phase image group. Insuch a case, identification information of individual phase image is notnecessary. However, the phase blood vessel management informationpreferably includes identification information of phase image group asidentification information of phase images when multiple phase imagescorrespond to one blood vessel identification information.

It does not matter how phase blood vessel location information isobtained. For example, phase blood vessel location information may beobtained as information indicating location on a blood vessel in phaseimage designated by hand etc. using a mouse or brush cursor, or may beobtained by detecting a region including characteristic pixels as bloodvessel from phase image using algorithm for detecting a region accordingto brightness etc. of pixels, for example. Further, phase blood vessellocation information may be obtained individually for the respectivephase information by the processing etc., or phase blood vessel locationinformation indicating the same location (region) as phase blood vessellocation information obtained for one phase image may be set as phaseblood vessel location information of other phase image in the same phaseimage group. It should be noted that examples of processing of detectinglocation of blood vessel in phase image and setting phase blood vessellocation information are described later.

The cross section blood vessel management information storage 1016stores cross section blood vessel management information including crosssection blood vessel location information that expresses location of ablood vessel in cross sectional image and blood vessel identificationinformation of blood vessel. The cross section blood vessel managementinformation may further include identification information foridentifying a corresponding cross sectional image. The identificationinformation etc. of a cross sectional image is same as theabovementioned identification information of phase image, so detaileddescription is omitted. Further, acquisition etc. of cross section bloodvessel location information is also same as the abovementioned phaseblood vessel location information, so detailed description is omitted.It should be noted that examples of processing of detecting location ofblood vessel in cross sectional image and setting cross section bloodvessel location information are described later.

The blood vessel management information storage 1017 stores one or moreblood vessel management information. The blood vessel managementinformation includes blood vessel location information that expresseslocation of at least one blood vessel in the living body image stored inthe living body image storage 1014 and blood vessel identificationinformation corresponding to blood vessel. Location of blood vessel istypically a region on one blood vessel in the living body; however, itmay be one site (coordinate) on blood vessel. Here, a method of definingarea of one blood vessel is arbitrary as long as identification ispossible as described above. Further, blood vessel managementinformation may include identification information for identifyingcorresponding living body. It should be noted that, for example, whenliving body images stored in the living body image storage 1014configures multiple living body images (living body image group)associated with time that are obtained by photographing one site in theliving body (for example, living body image group that is a moving imagewith frames of living body images is stored), it is possible to utilizeblood vessel location information associated with one living body imageas blood vessel location information of other living body imagesbelonging to the same living body image group. That is, common phaseblood vessel location information may be set for the respective livingbody images configuring one living body image group. In this case,identification information for identifying living body image group isused as identification information for identifying living body images.

It does not matter how blood vessel location information is obtained.For example, blood vessel location information may be obtained aslocation on a blood vessel in living body image designated by hand etc.using a mouse or brush cursor, or may be obtained by detecting a regionincluding characteristic pixels as blood vessel from living body imageusing algorithm for detecting a region according to brightness etc. ofpixels, for example. Further, blood vessel location information may beobtained individually for the respective living body information by theprocessing etc., or blood vessel location information indicating thesame location (region) as blood vessel location information obtained forone living body image may be set as blood vessel location information ofother living body image in the same living body image group. It shouldbe noted that examples of processing of detecting location of bloodvessel in living body image and setting blood vessel locationinformation are described later.

The change operation receiving part 1018 receives a change operation forchanging display of one of cross sectional image, phase image and bloodflow image that are displayed by the display 1022 described later.Specifically, the change operation is an operation carried out to oneimage and an operation in which the same change as this operation iscarried out to other images. Blood flow image may be a graph or listetc. expressing chronological variation of blood flow information thatis created using one or more blood flow information included in oneblood flow information group. Details of blood flow image are describedlater. The operation to any one of cross sectional image, phase imageand blood flow image displayed by the display 1022 is, for example,clicking, dragging etc. using a mouse, tapping etc. using touch paneletc., character inputting etc. using keyboard etc. to a region (orlocation in the vicinity thereof) in which any one of cross sectionalimage, phase image and blood flow image are displayed on a displaydevice such as a monitor (illustration omitted) etc. The operation toany one of cross sectional image, phase image and blood flow image mayalso be an operation of a button or pull-down menu displayed in oneimage.

The operation for changing display is, for example, an operation forchanging displayed image. The operation for changing displayed image is,for example, an operation for changing one image currently displayedthat is a target of operation to an image of the same kind that isassociated with different blood vessel identification information. Here,the image of the same kind means the three kinds, namely cross sectionalimage, phase image and blood flow image.

For example, the change operation receiving part 1018 receives, as thechange operation, an operation for designating a blood vessel to any oneof cross sectional image, phase image and blood flow image that aredisplayed by the display 1022. Then, the change operation receiving part1018 obtains blood vessel identification information corresponding tothe blood vessel designated by the change operation of designating ablood vessel. The change operation of designating a blood vessel may bean arbitrary predetermined operation and it is, for example, anoperation of sliding displayed cross sectional image or phase image inthe vertical direction, horizontal direction, etc. Further, it may be anoperation of pushing a button for changing blood vessel displayed incross sectional image, phase image and blood flow image being displayed,or an operation of selecting one blood vessel from a selection list ofblood vessels. Upon receiving such an operation, the change operationreceiving part 1018 obtains, from the cross section managementinformation (or phase management information), blood vesselidentification information different from blood vessel identificationinformation corresponding to the cross sectional image group (or phaseimage group) to which the cross sectional image (or phase image) beingdisplayed belongs.

Further, the operation for changing an image displayed is, for example,an operation for changing one image (target of operation) to an imageassociated with time different from time associated with this one image.

For example, the change operation receiving part 1018 receives a changeoperation of designating time to any one of cross sectional image, phaseimage and blood flow image that are displayed by the display 1022. Then,the change operation receiving part 1018 obtains time corresponding tothe change operation. The change operation of designating time may be anarbitrary predetermined operation, and, for example, when displayedblood flow image is a graph associated with time axis, the changeoperation is an operation of designating location of the graph otherthan the position indicating time corresponding to cross sectional imagecurrently displayed by clicking using a mouse etc. or tapping on a touchpanel. Alternatively, when blood flow information is a list indicatingmultiple blood flow information associated with time, the changeoperation is an operation of designating time other than the timecorresponding to cross sectional image currently displayed by clickingusing a mouse etc. Upon receiving such an operation, the changeoperation receiving part 1018 obtains, as the time corresponding to thechange operation, a value of time at a projected position of thedesignated position onto the time axis. Further, the change operation ofdesignating time may be an operation of sliding displayed crosssectional image or phase image in the vertical direction, horizontaldirection, etc. Alternatively, the change operation of designating timemay be an operation of sliding a slider bar (illustration omitted)indicating current playback time in the whole playback time of crosssectional image group or phase image group that is a moving image andbeing displayed in association with cross sectional image or phase imagebeing displayed.

Further, in the case in which the display 1022 sequentially synchronizestimes associated with cross sectional images and phase images anddisplays the cross sectional images and the phase images with presetframe rate, the change operation receiving part 1018 receives a framerate change operation for changing frame rate for displaying crosssectional images and phase images. The operation for changing frame rateis, for example, an operation of sliding a slider bar indicating framerate that is displayed on cross sectional image or phase image using amouse etc., an operation of pushing a button for receiving change offrame rate that is displayed on or near cross sectional image or phaseimage using a mouse etc., or an operation of inputting a value of framerate in a field for imputing a value that is displayed on crosssectional image or phase image using a keyboard etc. Upon receiving theframe rate change operation, the change operation receiving part 1018obtains a value of frame rate after the change, for example.

Further, the change operation receiving part 1018 may be configured toreceive phase blood vessel designating operation that is an operation ofdesignating location of a blood vessel in phase image displayed by thedisplay 1022. The operation of designating location of a blood vesselis, for example, an operation of clicking one or more sites on a regionin a phase image in which a blood vessel is displayed using a mouse orsurrounding the same using a mouse etc. Upon receiving the phase bloodvessel designating operation, the change operation receiving part 1018obtains blood vessel identification information corresponding to thelocation designated by the phase blood vessel designating operation fromthe phase blood vessel management information stored in the phase bloodvessel management information storage 1015. For example, blood vessellocation information including a coordinate clicked by a mouse etc. isdetected from the phase blood vessel management information, and bloodvessel identification information corresponding to the detected phaseblood vessel location information is obtained from the phase bloodvessel management information.

Further, as described later, when the display 1022 superposes anddisplays a cross sectional image and a phase image, the change operationreceiving part 1018 may receive a change operation, that is an operationof changing display, to any one of the superposed image of the crosssectional image and the phase image displayed by the display 1022 andblood flow image. In this case, the change operation receiving part 1018may receive substantially the same change operation as that received fora cross sectional image and a phase image as above. Further, when thechange operation is performed on the superposed image, the changeoperation receiving part 1018 may carry out processing similar to thatin the case of receiving the change operation performed on a crosssectional image or a phase image (for example, processing of obtainingblood vessel identification information, etc.).

For example, the change operation receiving part 1018 may receive bloodvessel change designating operation that is an operation of designatinga blood vessel in the image superposed by the display. The blood vesselchange designating operation is, for example, an operation ofdesignating location of blood vessel in the superposed image. Uponreceiving the blood vessel change designating operation, the changeoperation receiving part 1018 obtains blood vessel identificationinformation corresponding to the location indicated by the blood vesselchange designating operation in the similar way as above. The changeoperation receiving part 1018 may obtain blood vessel identificationinformation corresponding to the location indicated by the blood vesselchange designating operation from any of the cross sectional image andthe phase image superposed. Further, the change operation receiving part1018 may receive an operation for instructing superposition of a crosssectional image and a phase image.

Moreover, the change operation receiving part 1018 may be configured toreceive blood vessel designating operation that is an operation ofdesignating a location on one blood vessel in a living body imagedisplayed by the display 1022. The operation of designating a locationon one blood vessel is, for example, an operation of clicking one ormore sites on a region in a phase image in which one blood vessel isdisplayed using a mouse or surrounding the same using a mouse etc. Uponreceiving the blood vessel designating operation, the change operationreceiving part 1018 obtains blood vessel identification informationcorresponding to the location designated by the blood vessel designatingoperation from the blood vessel management information stored in theblood vessel management information storage 1017. For example, bloodvessel location information including a coordinate clicked by a mouseetc. is detected from the blood vessel management information, and bloodvessel identification information corresponding to the detected bloodvessel location information is obtained from the phase blood vesselmanagement information.

Here, reception of operations is a concept including: reception ofinformation input from input devices such as a keyboard, mouse, touchpanel etc.; reception of information transmitted through cable or radiocommunication; and reception of information read out from recordingmedia such as an optical disk, magnetic disk, semiconductor memory, etc.An input means for receiving an operation may be arbitrary such as anumeric keypad, keyboard, mouse, menu screen, etc. The change operationreceiving part 1018 may be realized by a device driver of an input meanssuch as a numeric keypad, keyboard, etc. or a control software of a menuscreen etc. The same applies to other receiving parts such as the bloodvessel classification designating operation receiving part 1019 etc.described later. Further, the change operation receiving part 1018 maycomprise an MPU and/or memory for executing the above processing, theprocedure thereof is typically realized by software, and this softwareis recorded in a recording media such as a ROM etc. However, it may berealized by hardware (dedicated circuits).

The blood vessel classification designating operation receiving part1019 receives blood vessel classification designating operation that isan operation of designating location of a vein or an artery in livingbody image displayed by the display 1022 described later. The operationof designating location of a vein in the blood vessel classificationdesignating operation is, for example, an operation of clicking one ormore sites on a region in a living body image, displayed by the display1022 described later, in which vein is displayed using a mouse orsurrounding the same using a mouse etc. Similarly, the operation ofdesignating location an artery in the blood vessel classificationdesignating operation is, for example, an operation of clicking one ormore sites on a region in a living body image, displayed by the display1022 described later, in which artery is displayed using a mouse orsurrounding the same using a mouse etc. For example, in the case inwhich an operation of designating location on a living body image byusing a mouse etc. after giving an instruction of performing anoperation of designating a vein to the blood vessel classificationdesignating operation receiving part 1019, this operation becomes anoperation of designating a vein. The same applies to the operation ofdesignating an artery.

The blood vessel classification management information storage 1020stores blood vessel classification management information includingblood vessel identification information and blood vessel classificationinformation that expresses whether a blood vessel is a vein or anartery. Moreover, the blood vessel identification information mayfurther include information that indicates the fact that determinationof whether a blood vessel is a vein or an artery has not been carriedout.

The blood vessel classification management information accumulating part1021 obtains blood vessel identification information corresponding tothe location designated by the blood vessel designating operation fromthe blood vessel management information stored in the blood vesselmanagement information storage 1017, and accumulates, in the bloodvessel classification management information storage 1020, blood vesselclassification management information including the obtained bloodvessel identification information and the blood vessel classificationinformation that expresses the blood vessel designating operationreceived by the blood vessel classification designating operationreceiving part 1019 (that is, information that expresses whether theblood vessel designated by the blood vessel designating operation is avein or an artery). For example, the blood vessel classificationmanagement information accumulating part 1021 obtains, from a livingbody image, information that expresses a coordinate or coordinate groupof the designated location(s) or the like as information that expressesthe location designated by the blood vessel designating operation,detects blood vessel location information including informationindicating the location obtained in the above from blood vesselmanagement information corresponding to a living body image that becomesa target of operation received as blood vessel designating operation,and obtains blood vessel identification information corresponding to thedetected blood vessel location information. Then, the blood vesselmanagement information associating the obtained blood vesselidentification information with blood vessel classification informationcorresponding to the blood vessel designating operation is accumulatedin the blood vessel management information storage 1017. The bloodvessel classification information corresponding to the blood vesseldesignating operation is, for example, information that expresseswhether the blood vessel corresponding to the location indicated byblood vessel classifying operation received before or after blood vesselclassifying operation is a vein or an artery.

The blood vessel classification management information accumulating part1021 is typically realized by an MPU and memory etc. The procedure ofthe blood vessel classification management information accumulating part1021 is typically realized by software, and this software is recorded inrecording media such as ROM etc. However, it may be realized by hardware(dedicated circuits).

The display 1022 synchronously displays cross sectional image includedin cross sectional image group and phase image included in phase imagegroup using time associated with the cross sectional image and the phaseimage, and displays a blood flow image that is an image expressingmultiple blood flow information, from among blood flow informationincluded in blood flow information group, associated with time within aperiod including time associated with the cross sectional image and thephase image being displayed. For example, the display 1022 preferablydisplays a cross sectional image and a phase image that are acquired atthe same period and for the same site. Further, the display 1022preferably displays blood flow image that is expressed by blood flowinformation associated with the same period of blood vessel included inthe same site as the site for which the cross sectional image and thephase image are acquired. Here, more preferably, the same period is thesame time. Further, the same site here may be considered to includeadjacent location with position gap like an error; however, it ispreferably the matched location.

Synchronously Displaying cross sectional image and phase image usingtime associated with the cross sectional image and the phase image meansdisplaying the cross sectional image and the phase image both associatedwith the same time, for example. Further, typically, cross sectionalimages included in cross sectional image group and phase images includedin phase image group are sequentially displayed, with the same framerate, so as to synchronize times associated with each other. The display1022 may display one cross sectional image and one phase image as stillimages, or may display cross sectional image and phase image as movingimages by sequentially reading out and displaying cross sectional imagesin one cross sectional image group and phase images one phase imagegroup.

The blood flow image an image created using multiple blood flowinformation, and, for example, a graph expressed in coordinate system inwhich multiple blood flow information associated with time are expressedwith the first axis showing time and the second axis showing values ofblood flow information, a list in which multiple blood flow informationassociated with time are arranged and expressed in ascending orderdescending order of time, or the like. Next, the display 1022, forexample, may obtain times associates with cross sectional image andphase image displayed, obtain blood flow image associated with timewithin a period including the obtained time, and simultaneously displaythe cross sectional image, the phase image and the blood flow image.

The inside of period including time associated with cross sectionalimage and phase image being displayed is a period of length previouslydesignated so as to including this time. The inside of period includingtime associated with cross sectional image and phase image beingdisplayed may be, for example, a period within a range obtained byadding a preset time to any one or both of front and rear of the timesassociated with cross sectional image and phase image being displayed.Further, it may be a period including times corresponding to all bloodflow information associated with cross sectional image group includingcross sectional image being displayed and phase image group includingphase image being displayed. For example, it may be a period between theearliest time of blood flow information and the latest time thereof. Forexample, in the case in which cross sectional image and phase imagebeing displayed are frame images of moving images, this period may varyin accordance with time corresponding to switched frame image (crosssectional image, phase image) every time frame image is switched, ortimes corresponding to cross sectional image and phase image beingdisplayed may be updated so as not to be included in the period setimmediately before.

Further, with respect to blood flow image, it is preferable to display,for example, values of blood flow information corresponding to timescorresponding to cross sectional image and phase image being displayedin a different display mode from other blood flow information. Thedifference of display modes means displaying with distinguishable aspectfrom other locations, and examples thereof includes overlaying differentcolors or patterns from other locations and displaying surroundingclosing line etc. so as to be distinguishable from other locations. Forexample, when blood flow image is a graph indicating blood flowinformation along time axis, straight lines indicating timescorresponding to cross sectional image and phase image being displayedmay be displayed perpendicularly to the time axis.

Further, the display 1022 may further display a living body image. Whenone or more living body images are associated with time, the living bodyimages may be synchronously displayed with cross sectional image andphase image.

In the case in which cross sectional image group, phase image group andblood flow information group are associated with blood vesselidentification information, in response to designation of one bloodvessel identification information, the display 1022 displays crosssectional image included in cross sectional image group associated withthis blood vessel identification information, phase image included inphase image group associated with this blood vessel identificationinformation, and blood flow image included in blood flow image groupassociated with this blood vessel identification information, forexample. Thereby, cross sectional image, phase image and blood flowimage for the same blood vessel may be displayed.

It should be noted that when the display 1022 further displays a livingbody image, it is preferable to display a living body image for whichone or more blood vessel identification information included in theblood vessel management information corresponding to this living bodyimage coincides with blood vessel identification informationcorresponding to cross sectional image, phase image and blood flow imagebeing displayed because there is relevance among images being displayed.

In embodiments, the display 1022, in particular, performs the samechange as the change corresponding to the change operation to crosssectional image, phase image and blood flow image displayed by thedisplay 1022. That is, when change operation to any one of crosssectional image, phase image and blood flow image being displayed isreceived by the change operation receiving part 1018, the display 1022carries out the change corresponding to the change operation to not onlythe image that is the target of the change operation but also otherimages. In other words, it is considered that the change to one image issynchronized with other images.

For example, when the change operation receiving part 1018 receiveschange operation, to one image, for displaying image corresponding toone blood vessel other than blood vessel corresponding to this image,the display 1022 changes all images displayed, including the image thatis a target of the change operation, to the above images correspondingto one blood vessel.

For example, the display 1022 obtains cross sectional image, phase imageand blood flow image corresponding to blood flow identificationinformation obtained by the change operation receiving part 1018 inresponse to change operation from cross sectional image group, phaseimage group and blood flow image group, and displays the imagesobtained. The obtainment from blood flow image group here is a conceptincluding obtainment of image such as the above blood flow imageconstructed using blood flow information included in blood flowinformation group, for example. Specifically, the display 1022 updatesthe displayed image with the obtained image. It should be noted thatregarding the respective images after change, it is possible to displaythe respective images of time corresponding to the images before change,or display the respective images of other time, for example, timecorresponding to starting time of any of the images.

Further, for example, when the change operation receiving part 1018receives change operation, to one image, for changing time that is atarget of display, the display 1022 changes all images displayed,including the image that is a target of change operation, to imagescorresponding to the time after the above change.

For example, the display 1022 obtains cross sectional image, phase imageand blood flow image corresponding to the time obtained by the changeoperation receiving part 1018 in response to change operation from crosssectional image group, phase image group and blood flow image group, anddisplays the images obtained. Specifically, currently displayed crosssectional image, phase image and blood flow image are respectivelyupdated by the obtained images.

Further, when the change operation receiving part 1018 receives bloodvessel identification information in response to change operation tophase image, the display 1022 obtains and displays blood vessel imageusing the blood vessel information group corresponding to this bloodvessel identification information obtained.

Further, when the change operation receiving part 1018 receives bloodvessel identification information in response to phase blood vesseldesignating operation, the display 1022 obtains cross section bloodvessel location information corresponding to the obtained blood vesselidentification information using cross section blood vessel managementinformation, and displays the location indicating the obtained crosssection blood vessel location information of the currently displayedcross sectional image in a different display aspect from otherlocations. The different display aspect is the same as above, and, forexample, the location indicated by cross section blood vessel locationinformation is overlaid in a preset color.

Further, when the change operation receiving part 1018 receives framerate change operation, the display 1022 changes frame rates fordisplaying cross sectional image and phase image to the same frame ratecorresponding to the change operation. For example, the display 1022changes frame rates for displaying cross sectional image and phase imageto one frame rate that is indicated by the value of frame rate obtainedby the change operation receiving part 1018 in response to frame ratechange operation and that is different from the current frame rate. Thechange in frame rate may be considered as change in reproduction speedof cross sectional images and phase images that are frame images.

Further, the display 1022 may synchronize cross sectional image includedin cross sectional image group and phase image included in phase imagegroup using times associated with cross sectional image and phase image,and superpose and display them. The superposition and display here meansthat contents of both images are displayed by permeability. For example,overlaying one image on the other image, or changing superposition modefrom usual superposition mode and displaying images means that at leastone image becomes semi-transparent and is superposed.

Further, when cross sectional image and phase image are superposed anddisplayed, the display 1022 may further display blood flow image that isan image expressing multiple blood flow information, from among bloodflow information included in blood flow information group, associatedwith time within a period including time associated with cross sectionalimage and phase image being superposed and displayed.

Further, in the case in which cross sectional image and phase image aresuperposed and displayed, when change operation similar to the above isperformed to one of the superposed image and blood flow image, thedisplay 1022 may apply the same change as the change corresponding tothis change operation to the superposed image of cross sectional imageand phase image as well as the blood flow image displayed by the display1022.

Further, the display 1022 may obtain blood vessel identificationinformation and phase blood vessel location information corresponding tophase image displayed by the display 1022 from phase blood vesselmanagement information, obtain blood vessel classification informationcorresponding to the blood vessel identification information from bloodvessel classification management information, and display locationindicated by the phase blood vessel location information correspondingto the blood vessel identification information of the phase image in adisplay aspect different from other locations, wherein the displayaspect is switched according to whether blood vessel classificationinformation corresponding to phase blood vessel location information isinformation indicating a vein or information indicating an artery. Forexample, it is possible to display location indicating a vein andlocation indicating an artery with different colors. Further, when bloodvessel classification information corresponding to phase blood vessellocation information is a value indicating no designation of any of veinand artery, it is possible to display the location indicated by thisphase blood vessel location information in a different display aspectfrom vein, artery, etc. It should be noted that in this case, thedisplay 1022 may display at least living body image and cross sectionalimage included in phase image group corresponding to one blood vesselidentification information.

The display here is a concept including display on display devices andprojection using projectors, and the like.

It may be thought that the display 1022 does or does not include adisplay device such as a display. The display 1022 may be realized bydriver software of display device, or driver software of display deviceand display device. Further, the display 1022 may be provided with anMPU and memory etc.; the procedure thereof is typically realized bysoftware, and this software is recorded in recording media such as ROMetc. However, it may be realized by hardware (dedicated circuits).

Next, actions of the image displaying apparatus 1000 are described withreferring to the flowchart of FIG. 9. Here, the case in which crosssectional image group and phase image group are moving images isdescribed as an example.

(Step S101)

The display 1022 starts displaying living body image. When the livingbody image is a frame image of moving image associated with time, thedisplay 1022 sequentially displays living body images with a presetframe rate.

(Step S102)

The display 1022 starts displaying cross sectional images included incross sectional image group. The display 1022 sequentially displayscross sectional images included in cross sectional image group with apreset frame rate. When the living body images that have been starteddisplaying in the above step is frame images, the display 1022synchronizes the cross sectional images with the living body images anddisplay the cross sectional images.

(Step S103)

The display 1022 starts displaying phase images included in crosssectional image group. The display 1022 sequentially displays phaseimages included in phase image group with a preset frame rate, andsynchronizes the phase images with the cross sectional images displayedin the Step S102. For example, cross sectional image and phase imageassociated with the same time are displayed simultaneously. It should benoted that cross sectional image and phase image displayed by thedisplay 1022 are images including blood vessels indicated in the livingimage displayed in the Step S101, for example.

(Step S104)

The display 1022 obtains time corresponding to the cross sectional imageor phase image being displayed, reads out blood flow information of aperiod, previously designated, including this time from the blood flowinformation storage 1013, and displays blood flow image created usingthe blood flow information read out. It should be noted that in thedisplay processing from the Step S101 to the Step S104, images relatedto the same time may be displayed simultaneously. In this case, thedisplay 1022 may obtain blood flow image in accordance with timecorresponding to the cross sectional image or phase image displayed inthe next processing, and simultaneously display this and the crosssectional image and phase image displayed in the next processing.

(Step S105)

The change operation receiving part 1018 judges whether operation fordisplaying superposed image of cross sectional image and phase image isreceived or not. If it is received, the processing transfers to the StepS106, and if it is not received, the processing transfers to the StepS107.

(Step S106)

The display 1022 synchronizes cross sectional images and phase imageswith each other using times associated with these images, and superposesand sequentially displays the cross sectional images and phase images.For example, the display 1022 carries out processing of displaying thesuperposed image instead of individual display of cross sectional imageand phase image. Then, processing returns to Step S105.

(Step S107)

The change operation receiving part 1018 judges whether or not anoperation to an image displayed by the display 1022 is received. If itis received, the processing transfers to the Step S108, and if it is notreceived, the processing transfers to the Step S109.

(Step S108)

The image displaying apparatus 1000 execute display processing inaccordance with the operation received in the Step S107. The details ofthis processing are described later. Then, the processing returns to theStep S105.

(Step S109)

The blood vessel classification designating operation receiving part1019 judges whether or not a blood vessel classification designatingoperation is received. If it is received, the processing transfers tothe Step S110, and if it is not received, the processing transfers tothe Step S111.

(Step S110)

The blood vessel classification management information accumulating part1021 obtains blood vessel classification management informationcorresponding to the blood vessel classification designating operationreceived in the Step S109, and accumulates it into the blood vesselclassification management information storage 1020. Then, the processingreturns to the Step S105.

(Step S111)

The display 1022 judges whether or not display processing in accordancewith the blood vessel classification management information will beexecuted. For example, it may be configured to determine that thedisplay processing will be carried out when the change operationreceiving part 1018 has received an operation for carrying out displayprocessing in accordance with the blood vessel classification managementinformation. Alternatively, it may be configured to determine that thedisplay processing will be carried out when blood vessel classificationmanagement information is accumulated. When the display processing iscarried out, the processing transfers to the Step S112, and if it is notcarried out, the processing transfers to the Step S113.

(Step S112)

The display 1022 carries out the display processing in accordance withblood vessel classification management information. Specifically,location in phase image that is indicated by the phase blood vessellocation information of blood vessel classification managementinformation is displayed in accordance with blood vessel classificationinformation in a different display aspect from other locations. Then theprocessing returns to the Step S105.

(Step S113)

The change operation receiving part 1018 judges whether or not anoperation for completing display processing by the display 1022 isreceived. If it is received, the processing ends, and if it is notreceived, the processing returns to the Step S105.

Next, details of actions corresponding to the Step S108 of FIG. 9 amongactions of the image displaying apparatus 1000 are described withreferring to FIG. 10.

(Step S201)

The change operation receiving part 1018 judges whether or not thereceived operation is a change operation. If it is a change operation,the processing transfers to the Step S202, and if it is not a changeoperation, the processing transfers to the Step S208.

(Step S202)

The change operation receiving part 1018 judges whether or not thereceived operation is a change operation for designating blood vessel.If it is a change operation for designating blood vessel, the processingtransfers to the Step S203, and if it is not a change operation fordesignating blood vessel, the processing transfers to the Step S205.

(Step S203)

The change operation receiving part 1018 obtains blood vesselidentification information of blood vessel designated by the changeoperation.

(Step S204)

The display 1022 changes, so as to display cross sectional image, phaseimage and blood flow image corresponding to the blood vesselidentification information obtained in the Step S203, display objects ofthese images. It should be noted that in the case in which crosssectional image and phase image are superposed, processing that issubstantially executed is the same except for processing of superposingand displaying these images. Then, the processing returns to upperprocessing.

(Step S205)

The change operation receiving part 1018 judges whether or not thereceived operation is a change operation for designating time. If it isa change operation for designating time, the processing transfers to theStep S206, and if it is not a change operation for designating time, theprocessing returns to upper processing. It should be noted that whenchange operation only includes one of an operation for designating bloodvessel and an operation for designating time, this processing may beomitted since it can be known that the change operation is an operationfor designating time in response to the judgment that it is not anoperation for designating blood vessel.

(Step S206)

The change operation receiving part 1018 obtains time indicated by thechange operation.

(Step S207)

The display 1022 changes times of the respective images displayed.Specifically, the display 1022 changes the display of cross sectionalimage, phase image and living body image to the display of crosssectional image, phase image and living body image corresponding to timeobtained in the Step S206. Further, the display 1022 changes the displayof blood flow image to the display of blood flow image created usingblood flow information of a period including time corresponding to thechanged cross sectional image or phase image. It should be noted that inthe case in which cross sectional image and phase image are superposed,processing that is substantially executed is the same except forprocessing of superposing and displaying these images. Then, theprocessing returns to upper processing.

(Step S208)

The change operation receiving part 1018 judges whether or not thereceived operation is phase blood vessel designating operation. If it isphase blood vessel designating operation, the processing transfers tothe Step S209, and if it is not phase blood vessel designatingoperation, the processing transfers to the Step S210. It should be notedthat when cross sectional image and phase image are not superposed,phase blood vessel designating operation is not received here.

(Step S209)

The change operation receiving part 1018 obtains blood vesselidentification information corresponding to phase blood vesseldesignating operation.

(Step S210)

The display 1022 displays blood flow image corresponding to phase bloodvessel designating operation. Specifically, blood flow image is obtainedusing blood flow information corresponding to the blood vesselidentification information obtained in the Step S209 and displayed.

(Step S211)

The display 1022 changes the display aspect of location of crosssectional image corresponding to phase blood vessel designatingoperation. Specifically, the display aspect of location of crosssectional image being displayed corresponding to phase blood vesseldesignating operation obtained in the Step S9 is changed to displayaspect different from other locations. Then, the processing returns toupper processing.

(Step S212)

The change operation receiving part 1018 judges whether or not thereceived operation is frame rate change operation to any of crosssectional image and phase image. If it is frame rate change operation,the processing transfers to the Step S213, and if it is not frame ratechange operation, the processing transfers to the Step S214. It shouldbe noted that even when cross sectional image and phase image aresuperposed, frame rate change operation to at least one of crosssectional image and phase image may be received here.

(Step S213)

The display 1022 changes frame rate at the time of displaying crosssectional image and phase image to the frame rate indicated by the framerate change operation. Then, the processing returns to upper processing.

(Step S214)

The change operation receiving part 1018 judges whether or not thereceived operation is blood vessel designating operation to living bodyimage. If it is blood vessel designating operation, the processingtransfers to the Step S215, and if it is not blood vessel designatingoperation, the processing returns to upper processing.

(Step S215)

The change operation receiving part 1018 obtains blood vesselidentification information corresponding to blood vessel designatingoperation.

(Step S216)

The display 1022 changes, so as to display cross sectional image, phaseimage and blood flow image corresponding to blood vessel identificationinformation obtained in the Step S215, a target of display of theseimages. It should be noted that in the case in which cross sectionalimage and phase image are superposed, processing that is substantiallyexecuted is the same except for processing of superposing and displayingthese images. Then, the processing returns to upper processing.

It should be noted that in the flowcharts illustrated in FIG. 9 and FIG.10, procedure of receiving operations etc. for cancelling superpositionprocessing of cross sectional image and phase image and displayprocessing of location in cross sectional image designated by phaseblood vessel designating operation and so on, and procedure ofcancelling these are omitted; however, in embodiments, it may beconfigured to carry out cancelling processing by receiving thesecancelling operation through receiving part (not illustrated).

Specific actions of the image displaying apparatus 1000 of the presentembodiment will be described in the following.

A conceptual diagram showing an example of the image displayingapparatus 1000 of the present embodiment is illustrated in FIG. 11.

FIG. 12 illustrates an example of living body image stored in the livingbody image storage 1014. It is assumed here that living body images arefundus images acquired for a fundus of one subject, as an example. It isalso assumed here that a fundus image is one frame image constructing aliving body image group (fundus image group) that consisting of multiplesequential living body images. This living body image is considered tobe a living body image, to which a time code “t1” is attached, amongliving body images configuring a living body image group named “E01” fora subject with subject identification information “P10001”. Here, a timecode is time attached to a living body image that is a frame image, andhere, it may be expressed as a combination of “year”, “month”, “day”,“hour”, “minute”, “second”, “frame” and the like, for example. It shouldbe noted here that to (n is an integer) is assumed to be a valueindicating arbitrary time. Here, values with the same n indicate thesame time. The same applies to the following as well. Each living bodyimage configuring a living body image group is associated with a timecode and stored in a file of the living body image group, for example.This time code is assumed here to indicate the day and time at whichframe images are acquired and the day and time at which data requiredfor acquiring frame images is acquired, for example. The same applies totime codes of other moving images. Further, living body images, crosssectional images, phase images, blood flow images etc. in the presentembodiment are images created for explanation, and there are cases inwhich the images are different from actual data.

FIG. 13 illustrates living body image management information formanaging living body images stored in the living body image storage1014. The living body image management information includes itemsincluding “subject ID”, “living body image group ID”, “time code” and“living body image”. The “subject ID” is identification information ofsubjects. The “living body image group ID” is identification informationof living body image groups, and here, a living body image groupconfigures one file and the living body image group ID is the file namethereof. Here, a living body image group associated with one “livingbody image group ID” consists of one or more fundus images acquiredwithin the same period for one eyeball of one subject. The “time code”is a time code, and is information of time associated with therespective living body images configuring a living body image group,here. In this specific example, cases are described in which thecombinations of the “living body image group ID” and “time code” areused as identification information of living body images. It should benoted that it may be considered that subject ID is also part ofidentification information of living body images. The “living bodyimage” is a living body image associated with a combination of livingbody image group ID and time code, and is a frame image here.

FIG. 14 illustrates blood vessel management information stored in theblood vessel management information storage 1014. The blood vesselmanagement information includes items including “subject ID”, “livingbody image group ID”, “time code”, “blood vessel ID” and “blood vessellocation information”. The “subject ID”, “living body image group ID”and “time code” are the same as in FIG. 13. The “blood vessel ID” isidentification information of blood vessels expressed in living bodyimages (fundus images here). The “blood vessel location information” isinformation indicating a region of a blood vessel corresponding to one“blood vessel ID” in a living body image, and consists of coordinategroup of pixels on a blood vessel corresponding to one “blood vessel ID”in a living body image here. It should be noted that in the presentembodiment, xr and xs (r and s are arbitrary integers) are assumed to bearbitrary values. The same applies to the following. For example, aregion 1051 surrounded by dotted lines is assumed to be a regionindicating blood vessel location information corresponding to bloodvessel ID “V01”. Here, the case in which blood vessel locationinformation is attached to each frame image is described; however, itmay be configured to utilize blood vessel location information that isset for one frame image also as blood vessel location information ofother frame images in the same living body image group.

It should be noted that ways of acquisition of blood vessel locationinformation from a living body image is arbitrary. For example, the usermay determine, as a blood vessel, a continuous area with brightness nomore than a threshold in an area traced by a cursor using a mouse etc.,and obtain information defining a region in the determined area (forexample, coordinates of pixels in the area, coordinates of pixelsconfiguring a contour of the area, etc.). It is possible toappropriately designate a region on blood vessel by doing so becauseblood vessels typically have tendency to be expressed in lowerbrightness than other sites. Further, it may be configured toautomatically detect a continuous area with brightness no more than athreshold in a living body image to obtain a line that connects centersin width direction of this area, and recognize the automaticallydetected area, an individual blood vessel, that has an intervalseparated by a junction and end point of this line. It should be notedthat such technology may be realized by utilizing technologies such asso-called automatic tracing etc. Blood vessel identification informationetc. may be automatically given in the acquisition order etc., or may bedesignated by the user, for example. Further, it may be configured togive blood vessel location information set for one frame image to otherframe images in the same living body image group as blood vessellocation information these other frame images.

FIG. 15 illustrates cross sectional image stored in the cross sectionalimage storage 1011. Here the cross sectional image is assumed to be across sectional image, imaged using OCT, of a cross sectionperpendicular to the fundus image illustrated in FIG. 12 at a locationcrossing one or more blood vessels in the fundus image, as an example.It should be noted that the cross sectional image is assumed to be oneframe image configuring a cross sectional image group that is a movingimage here. This cross sectional image is assumed to be a crosssectional image to which time code “t1” is attached among crosssectional images in the cross sectional image group with “D01” for asubject of subject identification information “P10001”. Here, a crosssectional image group is assumed to configure one file, and beassociated with this file name and stored in the cross sectional imagestorage 1011.

FIG. 16 illustrates cross section management information for managingcross sectional images stored in the Cross sectional image storage 1011.The cross section management information includes items including“subject ID”, “cross sectional image group ID”, “time code” and “crosssectional image”. The “subject ID” is identification information ofsubjects. The “cross sectional image group ID” is identificationinformation of cross sectional image groups, and here, a cross sectionalimage group configures one file and the cross sectional image group IDis the file name thereof. Here, a cross sectional image group associatedwith one “cross sectional image group ID” consists of multiple crosssectional images acquired within one period for one site of one fundusof one subject. The “time code” is a time code, and is information oftime associated with the respective cross sectional images configuring across sectional image group, here. In this specific example, cases aredescribed in which the combinations of the “cross sectional image groupID” and “time code” are used as identification information of crosssectional images. It should be noted that it may be considered thatsubject ID is also part of identification information of cross sectionalimages. The “cross sectional image” is a cross sectional imageassociated with a combination of cross sectional image group ID and timecode, and is a frame image here.

FIG. 17 illustrates cross section blood vessel management informationstored in the cross section blood vessel management information storage1016. The cross section blood vessel management information includesitems including “subject ID”, “cross sectional image group ID”, “timecode”, “blood vessel ID” and “cross section blood vessel locationinformation”. The “subject ID”, “cross sectional image group ID” and“time code” are the same in FIG. 16. The “blood vessel ID” is bloodvessel identification information of blood vessels expressed in crosssectional images. The “cross section blood vessel location information”is information indicating a region of blood vessel corresponding to one“blood vessel ID” expressed in a cross sectional image, and here, isconfigured by coordinate group of pixels on blood vessel correspondingto one “blood vessel ID” expressed in a cross sectional image. Forexample, in FIG. 12, the location indicated by a line 1052 indicates alocation (site) in which cross sectional image with cross sectionalimage group ID “D01” is acquired. Here, the case in which cross sectionblood vessel location information is attached to each frame image isdescribed; however, it may be configured to utilize blood vessellocation information that is set for one frame image also as crosssection blood vessel location information of other frame images in thesame cross sectional image group.

FIG. 18 illustrates phase image stored in the phase image storage 1012.Here the phase image is assumed to be a phase of the same location asthe cross sectional image shown in FIG. 14. It should be noted that thephase image is assumed to be one frame image configuring a phase imagegroup that is a moving image here. This phase image is assumed to be aphase image to which time code “t1” is attached among phase images inthe phase image group with “D01” for a subject of subject identificationinformation “P10001”. Here, a phase image group is assumed to configureone file, and be associated with this file name and stored in the phaseimage storage 1012.

FIG. 19 illustrates phase management information for managing phaseimages stored in the phase image storage 1012. The phase managementinformation includes items including “subject ID”, “phase image groupID”, “time code” and “phase image”. The “subject ID” is identificationinformation of subjects. The “phase image group ID” is identificationinformation of phase image groups, and here, a phase image groupconfigures one file and the phase image group ID is the file namethereof. Here, a phase image group associated with one “phase imagegroup ID” consists of multiple phase images acquired within one periodfor one site of one fundus of one subject. The “time code” is a timecode, and is information of time associated with the respective phaseimages configuring a phase image group, here. In this specific example,cases are described in which the combinations of the “phase image groupID” and “time code” are used as identification information of phaseimages. It should be noted that it may be considered that subject ID isalso part of identification information of phase images. The “phaseimage” is a living body image associated with a combination of phaseimage group ID and time code, and is a frame image here.

FIG. 20 illustrates phase blood vessel management information stored inthe phase blood vessel management information storage 1015. The phaseblood vessel management information includes items including “subjectID”, “phase image group ID”, “time code”, “blood vessel ID” and “phaseblood vessel location information”. The “subject ID”, “phase image groupID” and “time code” are the same in FIG. 19. The “blood vessel ID” isblood vessel identification information of blood vessels expressed inphase images. The “phase blood vessel location information” isinformation indicating a region of blood vessel corresponding to one“blood vessel ID” expressed in a phase image, and here, is configured bycoordinate group of pixels on blood vessel corresponding to one “bloodvessel ID” expressed in a phase image. Here, the case in which phaseblood vessel location information is attached to each frame image isdescribed; however, it may be configured to utilize blood vessellocation information that is set for one frame image also as phase bloodvessel location information of other frame images in the same phaseimage group. Further, in the case in which phase images corresponding toone time are acquired in accordance with cross sectional imageassociated with the same time, it may be configured to use cross sectionblood vessel location information set for a cross sectional imageacquired in the same location associated with the same time as phaseblood vessel location information of phase image of blood vessel.

FIG. 21 illustrates blood flow information management information storedin the blood flow information storage 1013. The blood flow informationmanagement information includes items including “subject ID”, “bloodflow information group ID”, “time code”, “blood vessel ID” and “bloodflow information”. Here, it is assumed that blood flow informationincluded in one blood flow information group configures one file, and“blood flow information group ID” is the file name thereof. Here, ablood flow information group associated with one “blood flow informationgroup ID” consists of multiple blood flow information acquired withinone period for one site of one fundus of one subject. Here, cases aredescribed in which the combinations of the “blood flow information groupID” and “time code” are used as identification information of blood flowinformation. It should be noted that it may be considered that subjectID is also part of identification information of blood flow information.The “blood flow information” is blood flow information, and here, isflow velocity as an example. It should be noted that a value “sp” (p isan arbitrary integer) is an arbitrary value indicating flow velocity ofblood.

For example, suppose that the user carries out an operation fordisplaying an image corresponding to the subject ID “P10001” using areceiving part (not illustrated) of the image displaying apparatus 1000.

The display 1022 reads out living body images in the order from therecord indicating “time code” of the earliest time among records (rows)corresponding to the subject ID “P10001” of living body managementinformation shown in FIG. 13, and sequentially displays them with apreset frame rate. Specifically, living body images are sequentiallyread out and displayed from the time code “t1”. The preset frame ratemay be a default frame rate, or may be a frame rate associated withliving body images. The display here is assumed to be display on amonitor (not illustrated).

Further, the display 1022 obtains one “cross sectional image group ID”,“D01” as an example here, from records (rows) corresponding to thesubject ID “P10001” of cross section management information shown inFIG. 16, reads out cross sectional images in the order from the recordindicating the same time code as the time code value “t1” correspondingthe abovementioned firstly displayed living body image from records inwhich the subject ID of the cross section management information is“P10001” and the cross sectional image group ID is “D01”, andsequentially displays them with the same frame rate as the living bodyimages. One “cross sectional image group ID” may be determined in anarbitrary way. For example, it is possible to select the “crosssectional image group ID” with the smallest value in number part fromamong multiple “cross sectional image group ID”, or use a “crosssectional image group ID” designated by the user. The display here isassumed to be display on a monitor (not illustrated).

When the display 1022 displays the cross sectional image of the crosssectional image group ID “D01” and corresponding time code value “t1”,the display 1022 obtains, from the cross section management informationshown in FIG. 17, the value of “blood vessel ID” associated with this“cross sectional image group ID” and this “time code”. Here, “v01” and“v02” are obtained. Then, the display 1022 obtains all the “blood vesselID”, sequentially by “phase image group ID”, from the record indicatingthe “time code” value “t1” and the “subject ID” “P10001” of phase bloodvessel management information shown in FIG. 19, and judges whether ornot the obtained “blood vessel ID” coincide with the “v01” and “v02”obtained in the above. This processing is repeated until detection ofcoincidence. Then, “phase image group ID” at the point of time when thecoincidence is detected is obtained. Here, the record “F01” in which the“phase image group ID” is “F01”, the “subject ID” is “P10001” and the“time code” is “2012/03/12_10:24:12.01” is obtained.

Next, the display 1022 obtains phase images with the “phase image groupID” “F01”, from records of phase management information, sequentially inthe order from the record of the “time code” “t1”, and displays themwith the same frame rate as the cross sectional images.

Accordingly, the living body images, the cross sectional images and thephase images are displayed in synchronous fashion.

Further, the display 1022 selects any one of the “blood vessel ID” “v01”and “v02” obtained for cross sectional images in the above. Thisselection may be determined in an arbitrary way, and here, for example,it is assumed that one with smaller number of the “blood vessel ID”,specifically “v01”, is selected. The display 1022: sequentially obtainsthe value of “time code” corresponding to cross sectional images to bedisplayed; obtains a period, wherein the center of the period is theobtained time code and the period is obtained by adding one secondbefore and after the center; detects the record having “time code”indicating time within the obtained period from the records in which thevalue of the “subject ID” in the blood flow information managementinformation shown in FIG. 21 is “P10001” and the value of the “bloodvessel ID” is the “v01” determined above; obtains the combination of thevalues of “blood flow information” and “time code” included in thedetected record; using this combination, generates, as a blood flowimage, a graph in which a first axis (for example, a horizontal axis)shows time indicated by the “time code” and a second axis (for example,a vertical axis) shows flow velocity indicated by the “blood flowinformation”; and displays the blood flow image. The display here isdisplay on a monitor (not illustrated). Further, here, an imageexpressed by a straight line that is perpendicular to the first axis isarranged at the position indicated by the “time code” associated withthe cross sectional image to be displayed.

FIG. 22 illustrates a display example of living body images, crosssectional images and phase images by the display 1022. Here, forconvenience of explanation, a display example of images, instead of thetiming immediately after the commencement of display, at the time “t100”that is the point of time when an arbitrary time has passed from thecommencement of display. In the diagram, living body image 1151, crosssectional image 1152, phase image 1153 and blood flow image 1154 arearranged and displayed so as not to overlap each other in a screen.

Here, for example, when the user moves the pointer 1181 onto the imagechange button 1155 located adjacent to the cross sectional image 1152and clicks it, the change operation receiving part 1018 obtains “bloodvessel ID” other than “v01” and “v02” that are “blood vessel ID”corresponding to the displayed cross sectional image such as oneobtained above from records in which the “subject ID” is “P10001” andthe value of the “time code” coincides with the “time code”corresponding to the cross sectional image being displayed from amongrecords of the cross section blood vessel management information shownin FIG. 17, and generates a list thereof. Here, applying so-calledunique processing to overlapping ones, they are deleted except for one.Then, the generated list 1167 is displayed below the image change button1155. It should be noted that information of this list may be previouslyobtained when displaying cross sectional images.

FIG. 23 illustrates an example of the list of “blood vessel ID”.

When the user selects “v03” from the list of FIG. 23 by manipulating amouse etc., the change operation receiving part 1018 receives a changeoperation for changing a cross sectional image that is a target ofdisplay to the cross sectional image corresponding to the blood vesselID “v03”. The display 1022 changes display of cross sectional image inaccordance with this change operation and carries out the same change asthe change of cross sectional image to other phase images and blood flowimages. That is, change of display is carried out so as to display thephase images and blood flow images corresponding to the blood vessel ID“v03”.

Specifically, the display 1022 obtains the value of “cross sectionalimage group ID” from the record in which the value of the “time code”coincides with the value of the time code of the cross sectional imagecurrently displayed and the “blood vessel ID” is “v03” from the crosssection blood vessel management information. Then, the display 1022reads out the “cross sectional image” associated with the obtained“cross sectional image group ID” and the value of the time code of thecross sectional image currently displayed from the cross sectionmanagement information shown in FIG. 16, and displays it instead of thecross sectional image displayed immediately before. For example, thecross sectional image displayed immediately before is overwritten.Subsequently, the display 1022 sequentially displays cross sectionalimages in the same cross sectional image group associated with the timecodes after the time code associated with this cross sectional image. Itshould be noted that instead of the time code of the cross sectionalimage currently displayed, the time code of the cross sectional imagedisplayed next may be used.

Similarly for phase images, the display 1022 obtains the value of “phaseimage group ID” from the record in which the value of the “time code”coincides with the value of the time code of the phase image currentlydisplayed and the “blood vessel ID” is “v03” from the phase blood vesselmanagement information. Then, the display 1022 reads out the “phaseimage” associated with the obtained “phase image group ID” and the valueof the time code of the phase image currently displayed from the phasemanagement information shown in FIG. 19, and displays it instead of thephase image displayed immediately before. For example, the phase imagedisplayed immediately before is overwritten. Subsequently, the display1022 sequentially displays phase images in the same phase image groupassociated with the time codes after the time code associated with thisphase image.

Further, relating blood flow images as well, the display 1022 obtains acombination of blood flow information associates with time code within aperiod including the value of the time code of the phase image currentlydisplayed as above and the blood vessel ID “v03”, generates a blood flowimage, and displays it instead of the phase image displayed immediatelybefore. Subsequently, the display 1022 sequentially obtains time codescorresponding to cross sectional images (or phase images) to bedisplayed, and sequentially obtains blood flow images using these timecodes as above to display the blood flow images.

From this, cross sectional images in which a blood vessel of the bloodvessel ID “v03” is expressed, phase images, and blood flow imagesrelated to this blood vessel are displayed on a monitor.

FIG. 24 illustrates a display example of living body images, crosssectional images, phase images and blood flow images by the display 1022after change of display. From this, it is possible to display images inwhich blood vessel corresponding to display content is changed inaccordance with a change operation.

Further, similarly, in the case in which the image change button 1156located adjacent to the phase image 1153 or the image change button 1157located adjacent to the blood flow image 1153 is pushed, a list of the“blood vessel ID” other than the “blood vessel ID” associated with therespective images corresponding to the pushed button, and further when a“blood vessel ID” is selected, similar processing to the above can beexecuted so as to display phase image, cross sectional image and bloodflow image corresponding to the selected “blood vessel ID”.

Further, in the state illustrated in FIG. 22, it is assumed, forexample, that the user moves the pointer 1181 to a location other thanthe line indicating the current time on the graph of the displayed bloodflow image 1154, and carries out clicking.

FIG. 25 illustrates a state in which the blood flow image is clicked.

The change operation receiving part 1018 obtains the value of time(value of time code) corresponding to the clicked location from the timeaxis that is a first axis of the blood flow image 1154. For example, theobtained value of time is “t88”. The change operation receiving part1018 receives a change operation for changing the blood flow image beingdisplayed to the blood flow image corresponding to the obtained time“t88”. The display 1022 changes the display of blood flow image inaccordance with this change operation, and carries out the same change,as the change executed to blood flow image, to other cross sectionalimages and phase images. That is, the change of display is executed soas to display the cross sectional image and phase image corresponding tothe time “t88”.

The display 1022: obtains a period, wherein the center of the period isthe time “t88” obtained by the change operation receiving part 1018 andthe period is obtained by adding one second before and after the center;detects the record having “time code” indicating time within theobtained period from the records in which the value of the “subject ID”in the blood flow information management information shown in FIG. 21 is“P10001” and the value of the “blood vessel ID” is the value “v01”corresponding to the blood vessel information that is a target currentlydisplayed; generates a blood flow image from the combination of thevalues of “blood flow information” and “time code” included in thedetected record in the same way as above; and displays the blood flowimage.

Further, the display 1022: displays cross sectional image included inthe record (row) in which the value of the “subject ID” coincides with“P10001”, the value of the “cross sectional image group ID” coincideswith “D01” that is the value of the “cross sectional image group ID”corresponding to the cross sectional image that is a display target, andthe value of the “time code” coincides with the time “t88” obtained bythe change operation receiving part 1018 from the cross sectionmanagement information shown in FIG. 16; and displays the crosssectional images included in the cross sectional image group whose valueof the “cross sectional image group ID” is “D01” sequentially in theorder according to the time codes.

Further, the display 1022: displays phase image included in the record(row) in which the value of the “subject ID” coincides with “P10001”,the value of the “phase image group ID” coincides with “F01” that is thevalue of the “phase image group ID” corresponding to the phase imagethat is a display target, and the value of the “time code” coincideswith the time “t88” obtained by the change operation receiving part 1018from the phase management information shown in FIG. 19; and displays thephase images included in the phase image group whose value of the “phaseimage group ID” is “F01” sequentially in the order according to the timecodes.

Further, the display 1022: displays living body image included in therecord (row) in which the value of the “subject ID” coincides with“P10001”, the value of the “living body image group Ill” coincides with“E01” that is the value of the “living body image group ID”corresponding to the living body image that is a display target, and thevalue of the “time code” coincides with the time “t88” obtained by thechange operation receiving part 1018 from the living body managementinformation shown in FIG. 13; and displays the living body imagesincluded in the living body image group whose value of the “living bodyimage group ID” is “E01” sequentially in the order according to the timecodes.

It is possible to display living body images, cross sectional images,phase images and blood flow images according to the time indicated bythe change operation by executing the change operation for changing timeto blood flow image in this way.

It should be noted that when an operation for changing time of imagedisplayed is carried out to cross sectional images or phase images aswell, the same processing as above is executed by obtaining the time anaccordance with this change information. It should be noted that theoperation for changing time to cross sectional images or phase imagesmay be received by a slider bar (illustration omitted) indicatingreproduction time of a moving image, for example.

Next, a case is described in which the user moves the pointer 1081 ontoone blood vessel in the displayed living body image 151 and performsclicking in the state illustrated in FIG. 22. The change operationreceiving part 1018 receives a blood vessel designating operation fordesignating a location on a blood vessel. This blood vessel designatingoperation is an operation for designating a blood vessel including theclicked location.

FIG. 26 illustrates a state in which the living body image is clicked.

Once receiving a blood vessel designating operation, the changeoperation receiving part 1018 obtains the coordinate of the designatedlocation (clicked location). For example, the obtained coordinate is(x33, y33). The change operation receiving part 1018 detects the recordhaving the coordinate that coincides with the above obtained coordinate(x33, y33) within one or more coordinates indicated by the “blood vessellocation information” from among the records (rows) in which the valueof the “subject ID” coincides with “P10001” and the value of the “timecode” coincides with the value “t100” corresponding to the living bodyimage being displayed in the blood vessel management informationillustrated in FIG. 14. Then, the value of the “blood vessel ID” of thedetected record is obtained as blood vessel identification informationcorresponding to the location indicated by the blood vessel designatingoperation. Here, the obtained value of the “blood vessel ID” is assumedto be “v03”, for example.

The display 1022 displays cross sectional images and phase imagescorresponding to the blood vessel ID “v03”, that is, cross sectionalimages and phase images including the blood vessel indicated by theblood vessel ID “v03” by carrying out the same processing as the case ofselecting the blood vessel ID “v03” from the list illustrated in FIG. 23as described above. Further, similar to the above, the display 1022displays blood flow images corresponding to the blood vessel ID “v03”,that is, blood flow images that are created using blood flow informationrelated to the blood vessel indicated by the blood vessel ID “v03”. Theimages thus displayed are similar to those in FIG. 24.

Accordingly, it is possible to display, using the display 1022, crosssectional images, phase images and blood flow images corresponding tothe blood vessel designated on living body images by the user. In thiscase, it is enough to designate a blood vessel and it is not required todesignate the site in which cross sectional images are acquired, sothere is no need to search the site in which cross sectional images areacquired for a blood vessel that the user wants to observe, and it ispossible to display cross sectional images etc. related to a bloodvessel arbitrarily designated for observing cross sectional images,therefore, labors are not required for searching the site in which crosssectional images are imaged, and easy and intuitive operation becomespossible.

Next, a case is described in which the user performs an operation forchanging frame rates of cross sectional images and phase images that aredisplay targets in the state illustrated in FIG. 22, for example. Forexample, it is assumed that the frame rate change button 1160 of thecross sectional image 1152 is clicked by using mouse etc. to input “15”fps (frame per second) etc. as a value of frame rate after the change.The change operation receiving part 1018 receives the frame ratechanging operation for changing the frame rate to “15” fps as the framerate changing operation in accordance with this operation.

The display 1022 changes the frame rate of displaying cross sectionalimages from the current frame rate to “15” fps. Further, the frame ratesof phase images and living body images are also changed to the sameframe rate. Then, cross sectional images, phase images and living bodyimages are sequentially displayed with the changed frame rate.

The same applies to the case in which a frame rate changing operation isperformed for changing the frame rate of phase images.

From this, when a frame rate changing operation is performed to any oneof cross sectional image and phase image, the frame rate of the imagethat is not the target of the change operation between the crosssectional image and phase image may be changed.

When the user selects, for example, a blood vessel designating buttonfor carrying out an operation for designating a blood vessel in phaseimages in the state illustrated in FIG. 22 and clicks a region on oneblood vessel in the phase image 1153 using a mouse, the change operationreceiving part 1018 receives this phase blood vessel designatingoperation for designating the location of a blood vessel in phase image.The phase blood vessel designating operation is an operation fordesignating the blood vessel including the clicked location.

Upon receiving the phase blood vessel designating operation, the changeoperation receiving part 1018 obtains the coordinate of the designatedlocation (clicked location). Suppose that the obtained coordinate is(x122, y122), for example. The change operation receiving part 1018detects the record having the coordinate that coincides with the aboveobtained coordinate (x122, y122) within one or more coordinatesindicated by the “blood vessel location information” from among therecords (rows) in which the value of the “subject ID” coincides with“P10001” and the value of the “time code” coincides with the value“t100” corresponding to the living body image being displayed in thephase blood vessel management information illustrated in FIG. 20. Then,the value of the “blood vessel ID” of the detected record is obtained asblood vessel identification information corresponding to the locationdesignated by the phase blood vessel designating operation. Here, theobtained value of the “blood vessel ID” is assumed to be “v02”, forexample.

The display 1022 detects the record in which the values of the “crosssectional image group ID” and “time code” respectively coincide with the“cross sectional image group ID” and “time code” corresponding to thecross sectional image being displayed and the value of the “blood vesselID” is the value “v02” obtained above from the records of the phaseblood vessel management information illustrated in FIG. 20, and obtainsthe value of the “phase blood vessel location information” of thedetected record. Then, the display 1022 overlays a preset color over theregion in the cross sectional image being displayed indicated by this“phase blood vessel location information”, thereby assigning the presetcolor to this region in the cross sectional image. This color ispreferably different from those of other regions in the cross sectionalimage. Then, the display 1022 displays, instead of the cross sectionalimage being displayed, a cross sectional image in which the color thuspreset is overlaid over the region indicated by the “phase blood vessellocation information”. For example, the cross sectional image displayedimmediately before is overwritten by the overlaid cross sectional image.

FIG. 27 illustrates a state in which blood vessel region in a crosssectional image corresponding to the phase blood vessel designatingoperation is displayed in a different aspect from other regions. In thisdiagram, the shaded region 1165 is supposed to be a site overlaid. Fromthis, when a blood vessel in a phase image is designated by a mouseetc., the location in a cross sectional image corresponding to thisblood vessel may be easily understandably displayed in a differentaspect from others.

Further, when the change operation receiving part 1018 receives thephase blood vessel designating operation and obtains the blood vessel ID“v02” in the same way as above, the display 1022: detects one or morerecords in which the value of the “blood flow image group ID” is the“blood flow image group ID” corresponding to the blood flow image beingdisplayed, the value of the “time code” is a value within the sameperiod as the period in which blood flow information corresponding tothe blood flow image being displayed is obtained, and the “blood vesselID” is the value “v02” from the records of the blood flow informationmanagement information illustrated in FIG. 21; obtains a combination ofthe value of the “blood flow information” included in the detected oneor more records and the value of the “time code”; obtains a blood flowimage using this combination; and display the obtained blood flow imageby replacing the blood flow image being displayed (for example,overwriting it). Accordingly, a blood flow image related to the bloodvessel designated in the phase image is displayed.

Further, for example, a case is described in which the user carries outan operation for superposing and displaying cross sectional images andphase images using a menu (not illustrated) etc. in the stateillustrated in FIG. 22. The change operation receiving part 1018receives an operation for superposing and displaying cross sectionalimages and phase images. Then, the display 1022 superposes and displayscross sectional images and phase images that are displayed after theoperation. When superposing and displaying them, the superposition iscarried out in a way in which the respective contents of the phaseimages and cross sectional images are simultaneously recognizable byvisual sensation etc. Specifically, the display 1022 at least superposesone image over the other image, wherein the transmittance of the oneimage is adjusted to become transparent. Alternatively, it is possibleto superpose imaged as overlay display, or superpose images usingcomposition mode such as multiplication mode in which the under imagemay be recognizable. Since phase images and cross sectional images to besuperposed are displayed synchronously as above, the phase images andcross sectional images in the superposed images are also synchronized.

FIG. 28 illustrates a state in which phase images and cross sectionalimages are superposed and displayed.

Further, in the case in which, as above, phase images and crosssectional images are superposed and the change operation receiving part1018 receives a change operation to any one of this superposed image andblood flow images, the display 1022 carries out change corresponding tothe change operation of the blood flow images that have been a target ofthe change operation, and further, carries out the same change as thechange corresponding to the change operation to the images that have notbeen the target of the change operation as well.

For example, when the change operation receiving part 1018 receives achange operation for changing time of blood flow images in the same wayas above, the display 1022, regarding the blood flow images, obtainsblood flow information and time codes within a period in which thecenter thereof is the time obtained in accordance with the changeoperation in the same way as above, and obtains and displays a bloodflow images. Further, regarding superposition of images, the display1022 may obtain cross sectional images and phase images corresponding tothe time obtained in accordance with the change operation in the sameway as above, and displays the superposed images. Further, this alsoapplies to the case in which a change operation for changing time of thesuperposed images is received. That is, it may be configured to obtainphase images, cross sectional images and blood flow images changed inaccordance with the change operation, and display superposed images forthe phase images and cross sectional images. Here, it is possible tocarry out the change operation in this case by considering that it is achange operation to one of the images superposed, or by considering thatit is a change operation to the both.

Further, the same also applies to the case of performing a changeoperation to blood flow images for changing blood vessel that is atarget of graph display, and the case of performing a change operationto superposed images for changing blood vessel displayed in the images.That is, it may be configured to obtain phase images, cross sectionalimages and blood flow images changed in accordance with the changeoperation, and display superposed images for the phase images and crosssectional images.

Further, it may be configured that a frame rate change operation to anyone of cross sectional images and phase images superposed and displayedis received, and that upon receiving the frame rate change operation,the respective frame rates of the cross sectional images and phaseimages to be superposed and displayed are changed to the frame ratecorresponding to the frame rate change operation (for example, the framerate designated by the frame rate change operation).

Further, for example, it is assumed that the user performs an operationfor designating a region on a vein among blood vessels in the livingbody image (fundus image) 1151 by pushing the button 1211 for performingan operation for designating a vein. For example, it is assumed that onepoint on a region on a blood vessel that is a vein is clicked using amouse. The state in which clicking is being carried out is the same asin the FIG. 26 except for the fact that the button 1211 is being pushed.

The blood vessel classification designating operation receiving part1019 receives a blood vessel classification designating operation fordesignating, as a vein, the blood vessel corresponding to the regionindicated by the blood vessel location information including the clickedcoordinate. It is assumed, for example, that the clicked coordinate is(x13, y13). The blood vessel classification management informationaccumulating part 1021 detects the record having the coordinate thatcoincides with the coordinate (x13, y13) corresponding to the bloodvessel classification designating operation received by the blood vesselclassification designating operation receiving part 1019 within thevalues of the “blood vessel location information” from among the records(rows) in which the value of the “subject ID” coincides with “P10001”,the “living body image group ID” coincides with “E01”, and the value ofthe “time code” coincides with the value “t100” corresponding to theliving body image being displayed in the blood vessel managementinformation illustrated in FIG. 14. Then, the blood vesselclassification management information accumulating part 1021 obtains thevalue of the “blood vessel ID” of the detected record as a “blood vesselID” indicating the blood vessel that is a vein. Here, for example, it isassumed that “vo1” is obtained as the “blood vessel ID” indicating theblood vessel that is a vein. The blood vessel classification managementinformation accumulating part 1021 accumulates blood vesselclassification management information including the obtained “bloodvessel ID”, blood vessel classification information indicating that itis a vein, and the subject ID “P10001” in the blood vesselclassification management information storage 1020.

Next, when the user selects the button 1212 etc. for performing anoperation for designating an artery and clicks, using a mouse, one pointin a region on an artery among blood vessels in the living body image1151, the blood vessel classification designating operation receivingpart 1019 receives a blood vessel classification designating operationfor designating, as an artery, the blood vessel corresponding to theregion indicated by the blood vessel location information including theclicked coordinate. It is assumed, for example, that the clickedcoordinate is (x22, y22). The blood vessel classification managementinformation accumulating part 1021 detects the record having thecoordinate that coincides with the coordinate (x22, y22) correspondingto the blood vessel classification designating operation received by theblood vessel classification designating operation receiving part 1019within the values of the “blood vessel location information” from amongthe records (rows) in which the value of the “subject ID” coincides with“P10001” and the value of the “time code” coincides with the value“t100” corresponding to the living body image currently displayed in theblood vessel management information illustrated in FIG. 14. Then, theblood vessel classification management information accumulating part1021 obtains the value of the “blood vessel ID” of the detected recordas a “blood vessel ID” indicating the blood vessel that is an artery.Here, for example, it is assumed that “vo2” is obtained as the “bloodvessel ID” indicating the blood vessel that is an artery. The bloodvessel classification management information accumulating part 1021accumulates blood vessel classification management information includingthe obtained “blood vessel ID”, blood vessel classification informationindicating that it is an artery, and the subject ID “P10001” in theblood vessel classification management information storage 1020.

FIG. 29 illustrates an example of blood vessel classification managementinformation stored in the blood vessel classification managementinformation storage 1020. Here, as an example, a case is illustrated inwhich other blood vessel classification management information isalready stored in the blood vessel classification management informationstorage 1020. The blood vessel classification management informationincludes “subject ID”, “blood vessel ID” and “blood vesselclassification information”. The “blood vessel classificationinformation” is blood vessel classification information, and here, it issupposed that the value is “artery” when a blood vessel is a vein andthe value is “vain” when a blood vessel is an artery.

Next, suppose that the user manipulates a menu (illustration omitted)etc. to carry out an operation for reflecting blood vesselclassification information stored in the blood vessel classificationmanagement information storage 1020 to the phase images currentlydisplayed. When this operation is received by the change operationreceiving part 1018, the display 1022 reads out the value of the “bloodvessel ID” corresponding to the cross sectional images currentlydisplayed from the phase blood vessel management information illustratedin FIG. 20. Specifically, the display 1022: reads out values “v01” and“v02” of the “blood vessel ID” of the record in which the value of the“subject ID” coincides with “P10001”, the value of the “cross sectionalimage group ID” coincides with “F01” and the value of the “time code”coincides with the value “t100” corresponding to the living body imagecurrently displayed; detects the record in which the value of the “bloodvessel ID” coincides with any of these in the blood vesselclassification management information illustrated in FIG. 29; andobtains a combination of the value of the “blood vessel classificationinformation” and the value of the “blood vessel ID” in the detectedrecord. Here, it is assumed that a first combination of the blood vesselID “v01” and blood vessel classification information “vein” and a secondcombination of the blood vessel ID “v02” and blood vessel classificationinformation “artery” are obtained.

The display 1022 detects the record in which the value of the “bloodvessel ID” coincides with “v01” that is the value of the “blood vesselID” of the first combination obtained as above among the recordscorresponding to the phase image currently displayed in the phase bloodvessel management information illustrated in FIG. 20, and obtains thevalue of the “phase blood vessel location information” of the detectedrecord. Then, the display 1022 changes display aspect of the region inthe phase image currently displayed indicated by this “phase bloodvessel location information” (that is, the region on the blood vesselindicated by the blood vessel ID “v01”) to the display aspect previouslyassociated with “vein” that is the value of the “blood vesselclassification information” of the first combination obtained in theabove. For example, a preset color is overlaid on this region.

The display 1022 detects the record in which the value of the “bloodvessel ID” coincides with “v02” that is the value of the “blood vesselID” of the second combination obtained as above among the recordscorresponding to the phase image currently displayed in the phase bloodvessel management information illustrated in FIG. 20, and obtains thevalue of the “phase blood vessel location information” of the detectedrecord. Then, the display 1022 changes display aspect of the region inthe phase image currently displayed indicated by this “phase bloodvessel location information” (that is, the region on the blood vesselindicated by the blood vessel ID “v02”) to the display aspect previouslyassociated with “artery” that is the value of the “blood vesselclassification information” of the second combination obtained in theabove. For example, a preset color is overlaid on this region. Here,information designating display aspects is accumulated in a recordingmedium (not illustrated) in association with each blood vesselclassification information such that the display aspects of the bloodvessel classification information “vein” and blood vessel classificationinformation “artery” become distinguishable. For example, informationassociating the blood vessel classification information “vein” withoverlaying color “red” and information associating the blood vesselclassification information “artery” with overlaying color “blue” areaccumulated in advance. Then, the display 1022 uses these information tooverlay blue on the region corresponding to the above blood vessel ID“v01” and overlay red on the region corresponding to the above bloodvessel ID “v02”.

FIG. 30 illustrates an example of the case in which blood vesselclassification management information is reflected to phase images andsuch phase images are displayed. In the diagram, the region 1231 is aregion corresponding to the above blood vessel ID “v01”, and the region1232 is a region corresponding to the above blood vessel ID “v02”. Fromsuch display, it becomes possible to clearly express vein portions andartery portions of phase images. Further, designation of vain/artery maybe carried out from living body images such as fundus images, therebyjudgment is easy and operability is outstanding.

It should be noted that a case in which blood vessel classificationmanagement information is reflected to phase images is described;however, blood vessel classification management information may bereflected to cross sectional images. In this case, information utilizedfor phase images may be replaced by information corresponding to crosssectional images.

Further, blood vessel classification management information is reflectedto phase images according to operations of the user in this example;however, it may be configured to reflect blood vessel classificationmanagement information to phase images as default, and in response toevery reception of blood vessel classification designating operation,change the display of phase images including corresponding blood vessel.

It should be noted that in this specific example, a case is described inwhich cross sectional images and phase images in which blood vesselidentification information associated with the same time as crosssectional images and phase images being displayed are different whendisplaying cross sectional images and phase images in which blood vesselidentification information are different; however, it may be configuredto display cross sectional images and phase images in which blood vesselidentification information corresponding to the time associated withcross sectional images and phase images displayed immediately after thecross sectional images and phase images being displayed. This is thesame in the case of displaying cross sectional images and phase imagesin which regions on blood vessels in the cross sectional images andphase images are displayed in a different aspect from other regions, forexample.

According to the present embodiment as above, when the display 1022displays cross sectional images, phase images and blood flow imagesacquired for the same site in the living body, and when a changeoperation for changing the display of any one of the cross sectionalimages, phase images and blood flow images, change of display accordingto the change operation is carried out for the target image of thechange operation and the same change as the change operationcorresponding to this change operation for other images, thereby beingcapable of establishing correspondence among the multiple images evenwhen the change operation is carried out, and therefore, change ofdisplay can be executed appropriately for the multiple images acquiredfor the same site in the living body.

Further, since cross sectional images and phase images acquired for thesame site in the living body are superposed and displayed, it becomespossible to compare corresponding sites in the cross sectional imagesand phase images exceedingly accurately and easily.

Further, upon designating whether a blood vessel in living body imagesis a vein or an artery, this designation is reflected as the displayaspect of a region in phase images in which the blood vessel isdisplayed; therefore, individual designation for classifying bloodvessel to the respective images, and so operation may be simplified.

It should be noted that in the present embodiment, as in the case inwhich phase images are created using the same information as informationutilized for acquiring cross sectional images or blood flow images,cases are described in which correspondence between phase images andcross sectional images is established; however, when correspondencebetween phase images and cross sectional images is not established, thedisplay may be configured to change image size of at least one of phaseimages and cross sectional images such that the region indicated by thephase blood vessel location information respectively corresponding tophase images and cross sectional images to be superposed and the regionindicated by the cross sectional blood vessel location information areoverlapped with each other in the same height or width, and superposethese images.

Further, in each of the above embodiments, each processing may berealized by centralized processing of a single apparatus (system), oralternatively, may be realized by distributed processing of multipleapparatus.

Further, needless to say, two or more communication means (informationtransmitter etc.) existed in one apparatus may be realized by one mediumphysically in each of the above embodiments.

Further, cases in which an image displaying apparatus is standalone aredescribed in each of the above embodiments; however, an image displayingapparatus may be a standalone apparatus or may be a server apparatus ina server/client system. In the latter case, the display and/or receivingpart receive inputs via a communication line and display a screen.

It should be noted that software that realizes an image displayingapparatus is a program described below. That is, this program is aprogram configured to cause a computer that is accessible to: a crosssectional image storage configured to store a cross sectional imagegroup including multiple cross sectional images each of which isassociated with time and expresses a cross section intersecting at leastone blood vessel of a living body; a phase image storage configured tostore a phase image group including multiple phase images each of whichis associated with time and expresses chronological variation of phasedifference at a cross section intersecting at least one blood vessel ofthe living body; and a blood flow information storage configured tostore a blood flow information group including multiple blood flowinformation each of which is related to blood flow in a blood vessel ofthe living body and is associated with time, to function as: a displayconfigured to synchronously display a cross sectional image included inthe cross sectional image group and a phase image included in the phaseimage group using time associated with the cross sectional image and thephase image, and display a blood flow image that expresses multipleblood flow information, from among the blood flow information includedin the blood flow information group, associated with time within aperiod including time associated with the cross sectional image and thephase image that are being displayed; and a change operation receivingpart configured to receive a change operation for changing display ofone of the cross sectional image, the phase image and the blood flowimage that are displayed by the display, wherein the display performsthe same change as the change corresponding to the change operation tothe cross sectional image, the phase image and the blood flow image thatare displayed by the display.

Further, this program is a program configured to cause a computer thatis accessible to: a cross sectional image storage configured to store across sectional image group including multiple cross sectional imageseach of which is associated with time and expresses a cross sectionintersecting at least one blood vessel of a living body; and a phaseimage storage configured to store a phase image group including multiplephase images each of which is associated with time and expresseschronological variation of phase difference at a cross sectionintersecting at least one blood vessel of the living body, to functionas: a display configured to synchronously and superposedly display across sectional image included in the cross sectional image group and aphase image included in the phase image group using time associated withthe cross sectional image and the phase image.

Further, this program is a program configured to cause a computer thatis accessible to: a living body image storage configured to store aliving body image acquired by photographing a living body; a bloodvessel management information storage configured to store blood vesselmanagement information including blood vessel location information thatexpresses location of at least one blood vessel in the living body imageand blood vessel identification information corresponding to this bloodvessel; a phase image storage configured to store phase managementinformation that includes a phase image group including multiple phaseimages each of which is associated with time and expresses chronologicalvariation of phase difference at a cross section intersecting at leastone blood vessel of the living body and blood vessel identificationinformation of a blood vessel intersecting a cross section correspondingto the phase image group; a phase blood vessel management informationstorage configured to store phase blood vessel management informationincluding phase blood vessel location information that expresseslocation of a blood vessel in the phase image and blood vesselidentification information of this blood vessel; and a blood vesselclassification management information storage configured to store bloodvessel classification management information including blood vesselidentification information and blood vessel classification informationthat expresses whether a blood vessel is a vein or an artery, tofunction as: a display configured to display the living body image and aphase image included in the phase image group that is associated withone blood vessel identification information; a blood vesselclassification designating operation receiving part configured toreceive blood vessel classification designating operation fordesignating location of a vein or an artery in the living body imagedisplayed by the display; and a blood vessel classification managementinformation accumulating part configured to obtain blood vesselidentification information corresponding to the location designated bythe blood vessel designating operation from the blood vessel managementinformation, and accumulate, in the blood vessel classificationmanagement information storage, blood vessel classification managementinformation including this blood vessel identification information andthe blood vessel classification information that expresses whether theblood vessel designated by the blood vessel designating operation is avein or an artery, wherein the display obtains the blood vesselidentification information and the phase blood vessel locationinformation corresponding to the phase image displayed by the displayfrom the phase blood vessel management information, obtains the bloodvessel classification information corresponding to this blood vesselidentification information from the blood vessel classificationmanagement information, and displays the location expressed by the phaseblood vessel location information corresponding to the blood vesselidentification information of the phase image in a different displayaspect from other locations, wherein the display aspect thereof dependson whether the blood vessel classification information corresponding tothis phase blood vessel location information is information expressing avein or information expressing an artery.

It should be noted that regarding the above programs, functions that canbe realized only by hardware are not included in the functions realizedby the above programs. For example, functions that can be realized onlyby hardware such as a modem and interface cards in an obtaining partconfigured to obtain information and a display configured to displayinformation are not included in the functions realized by the aboveprograms.

Further, the number of computer that executes this program may be one ormore. That is, centralized processing may be applied, or alternatively,distributed processing may be applied.

FIG. 31 is a schematic diagram illustrating an example of the appearanceof a computer that realizes an image displaying apparatus according tothe above embodiment. The above embodiment may be realized by computerhardware and computer program executed by the computer hardware.

In FIG. 31, the computer system 900 is provided with a computer 901including CD-ROM (Compact Disk Read Only Memory) drive 905 and FD(Floppy (registered trademark) Disk) drive 906, a keyboard 902, a mouse903, and a monitor 904.

FIG. 32 illustrates internal configuration of the computer system 900.In FIG. 32, in addition to the CD-ROM drive 905 and FD drive 906, thecomputer 901 includes MPU (Micro Processing Unit) 911, ROM 912 forstoring programs such as a boot-up program, RAM (Random Access Memory)913 that is connected with the MPU 911, temporally stores commands ofapplication programs and provides a temporally storing space, hard disk914 that stores application programs, system programs and data, and bus915 that connects the MPU 911, ROM 912 etc. with each other. It shouldbe noted that the computer 901 may include a network card (notillustrated) that provides connection to LAN.

Programs that cause the computer system 900 to execute functions of animage displaying apparatus and so on according to the above embodimentsmay be stored in CD-ROM 921 or FD 922, inserted into the CD-ROM drive905 or FD drive 906, and/or transmitted to the hard disk 914. Instead ofthese, the programs may be transmitted to a computer 901 via a network(not illustrated), and/or stored in the hard disk 914. At the time ofexecution, a program is loaded onto the RAM 913. It should be noted thata program may be directly loaded from the CD-ROM 921, FD 922 or network.

It is not necessary for a program to include an operating system (OS) orthird-party program and so on that causes the computer 901 to executefunctions of an image displaying apparatus and so on according to theabove embodiments. A program may include only part of commands forcalling appropriate functions (modules) in a controlled mode andobtaining desired results. Since ways of operations of the computersystem 900 are widely known, detailed description is omitted.

The combination of the image displaying apparatus 1000 of the presentembodiment and the optical image measuring apparatus of the aboveembodiment may be regarded as a measuring system, for example.

An image displaying apparatus according to the present embodiment issuitable as an apparatus etc. that displays multiple images acquired fora living body, and in particular, useful as an apparatus etc. thatdisplays multiple images related to one site in a living body acquiredusing OCT and the like.

EXPLANATION OF SYMBOLS

-   1 fundus observation apparatus (optical image measuring apparatus)-   2 retinal camera unit-   10 illumination optical system-   30 imaging optical system-   31 focusing lens-   31A focus driver-   41 optical path length changing part-   42 galvano scanner-   50 alignment optical system-   60 focus optical system-   100 OCT unit-   101 light source unit-   105 optical attenuator-   106 polarization controller-   115 CCD image sensor-   200 arithmetic and control unit-   210 controller-   211 main controller-   212 storage-   220 image forming part-   221 cross sectional image forming part-   222 phase image forming part-   230 image processor-   231 blood vessel region specifying part-   232 blood flow information generating part-   233 gradient calculating part-   234 blood flow velocity calculating part-   235 blood vessel diameter calculating part-   236 blood flow amount calculating part-   237 cross section setting part-   240A display-   240B operation part-   E eye-   Ef (eye) fundus-   LS signal light-   LR reference light-   LC interference light-   1000 image displaying apparatus-   1011 cross sectional image storage-   1012 phase image storage-   1013 blood flow information storage-   1014 living body image storage-   1015 phase blood vessel management information storage-   1016 cross section blood vessel management information storage-   1017 blood vessel management information storage-   1018 change operation receiving part-   1019 blood vessel classification designating operation receiving    part-   1020 blood vessel classification management information storage-   1021 blood vessel classification management information accumulating    part-   1022 display

What is claimed is:
 1. An optical image measuring apparatus, comprising:an optical system configured to split light from a light source intosignal light and reference light, and detect interference light betweenscattered light of the signal light from a living body and the referencelight having traveled by way of a reference optical path; a scannerconfigured to carry out a first scan in which a first cross section thatintersects an interested blood vessel in the living body is repeatedlyscanned with the signal light; an image forming part configured to forma first cross sectional image that expresses chronological variation ofmorphology of the first cross section and a phase image that expresseschronological variation of phase difference based on the detectionresults of the interference light acquired by the optical system duringthe first scan; a blood vessel region specifying part configured tospecify a blood vessel region corresponding to the interested bloodvessel for each of the first cross sectional image and the phase image;and a blood flow information generating part configured to generateblood flow information related to the interested blood vessel based onthe blood vessel region of the first cross sectional image and thechronological variation of phase difference within the blood vesselregion of the phase image.
 2. The optical image measuring apparatus ofclaim 1, wherein the scanner carries out a second scan in which a secondcross section that intersects the interested blood vessel and is locatedin the vicinity of the first cross section is scanned with the signallight, the image forming part forms a second cross sectional image thatexpresses morphology of the second cross section based on the detectionresults of the interference light acquired by the optical system duringthe second scan, the blood vessel region specifying part specifies ablood vessel region corresponding to the interested blood vessel in thesecond cross sectional image, and the blood flow information generatingpart generates the blood flow information based on the distance betweenthe first cross section and the second cross section, the blood vesselregion of the first cross sectional image, the blood vessel region ofthe second cross sectional image, and the chronological variation ofphase difference.
 3. The optical image measuring apparatus of claim 2,wherein the blood flow information generating part comprises a gradientcalculating part configured to calculate gradient of the interestedblood vessel at the first cross section based on the distance, the bloodvessel region of the first cross sectional image and the blood vesselregion of the second cross sectional image, and generates the blood flowinformation based on calculation result of the gradient and thechronological variation of phase difference.
 4. The optical imagemeasuring apparatus of claim 3, wherein the second cross sectionincludes a cross section located in the upstream of the interested bloodvessel from the first cross section and a cross section located in thedownstream.
 5. The optical image measuring apparatus of claim 3, whereinthe gradient calculating part calculates the gradient based on locationof the blood vessel region of the first cross sectional image andlocation of the blood vessel region of the second cross sectional image.6. The optical image measuring apparatus of claim 3, wherein the bloodflow information generating part comprises a blood flow velocitycalculating part configured to calculate blood flow velocity of theblood that flows within the interested blood vessel at the first crosssection based on calculation result of the gradient and thechronological variation of phase difference.
 7. The optical imagemeasuring apparatus of claim 6, wherein the blood flow velocitycalculating part generates blood flow velocity variation informationthat expresses chronological variation of the blood flow velocity basedon calculation result of the gradient and the chronological variation ofphase difference.
 8. The optical image measuring apparatus of claim 7,wherein the blood flow velocity calculating part calculates a statisticof the blood flow velocity based on the blood flow velocity variationinformation.
 9. The optical image measuring apparatus of claim 7,further comprising a photographing part configured to photograph a siteof the living body including the location of the first cross section,wherein the blood flow information generating part comprises: a bloodvessel diameter calculating part configured to calculate diameter of theinterested blood vessel at the first cross section based on an image ofthe site photographed by the photographing part; and a blood flow amountcalculating part configured to calculate amount of blood flow within theinterested blood vessel based on the blood flow velocity variationinformation and the calculation result of the diameter.
 10. The opticalimage measuring apparatus of claim 7, wherein the blood flow informationgenerating part comprises: a blood vessel diameter calculating partconfigured to calculate diameter of the interested blood vessel at thefirst cross section based on the first cross sectional image; and ablood flow amount calculating part configured to calculate amount ofblood flow within the interested blood vessel based on the blood flowvelocity variation information and the calculation result of thediameter.
 11. The optical image measuring apparatus of claim 7, whereinthe blood flow velocity calculating part generates the blood flowvelocity variation information for each of multiple pixels included inthe blood vessel region of the phase image, and the blood flowinformation generating part comprises a blood flow amount calculatingpart configured to calculate blood flow amount for the respective pixelsby time-integrating the blood flow velocity variation information forthe respective pixels, and calculate blood flow amount within theinterested blood vessel by adding the blood flow amounts for themultiple pixels.
 12. The optical image measuring apparatus of claim 1,wherein the blood vessel region specifying part analyzes the first crosssectional image to specify blood vessel region, specifies image regionof the phase image corresponding to the location of this blood vesselregion of the first cross sectional image, and sets this specified imageregion as blood vessel region of the phase image.
 13. The optical imagemeasuring apparatus of claim 1, wherein the scanner carries out thefirst scan over at least one cardiac cycle of the living body.
 14. Theoptical image measuring apparatus of claim 1, wherein the interestedblood vessel is a blood vessel in an eye fundus.
 15. The optical imagemeasuring apparatus of claim 14, wherein the blood vessel is set in thevicinity of an optic papilla of the eye fundus.
 16. The optical imagemeasuring apparatus of claim 2, further comprising: an image obtainingpart configured to detect reflected light of illumination lightirradiated onto eye fundus of the living body to obtain an image of theeye fundus, wherein part of optical path thereof is common to theoptical system; a display configured to display the image obtained; anoperation part configured for designating the first cross section to theimage displayed; and a cross section setting part configured to set thesecond cross section based on the first cross section designated and theimage obtained, wherein the scanner carries out the first scan of thefirst cross section designated and carries out the second scan of thesecond cross section set.
 17. An optical image measuring apparatus,comprising: an optical system configured to split light from a lightsource into signal light and reference light, and detect interferencelight between scattered light of the signal light from a living body andthe reference light having traveled by way of a reference optical path;a scanner configured to carry out a first scan in which a first crosssection that intersects an interested blood vessel in the living body isrepeatedly scanned with the signal light, and carry out a second scan inwhich a second cross section that intersects the interested blood vesseland is located in the vicinity of the first cross section is scannedwith the signal light; an image forming part configured to form a firstcross sectional image that expresses chronological variation ofmorphology of the first cross section and a phase image that expresseschronological variation of phase difference based on the detectionresults of the interference light acquired by the optical system duringthe first scan, and form a second cross sectional image that expressesmorphology of the second cross section based on the detection results ofthe interference light acquired by the optical system during the secondscan; a photographing part configured to photograph a site of the livingbody including the location of the first cross section; a blood vesselregion specifying part configured to specify a blood vessel regioncorresponding to the interested blood vessel for each of the first crosssectional image, the phase image and the second cross sectional image; ablood flow velocity calculating part configured to calculate blood flowvelocity of the blood that flows within the interested blood vessel atthe first cross section based on the chronological variation of phasedifference and the specification result of the blood vessel region; ablood vessel diameter calculating part configured to calculate diameterof the interested blood vessel at the first cross section based on thephotographed image of the site by the photographing part; and a bloodflow amount calculating part configured to calculate amount of bloodflow within the interested blood vessel based on calculation result ofthe blood flow velocity and the calculation result of the diameter. 18.The optical image measuring apparatus of claim 17, wherein the scannercarries out the first scan over at least one cardiac cycle of the livingbody.
 19. The optical image measuring apparatus of claim 17, wherein theinterested blood vessel is a blood vessel in an eye fundus.
 20. Theoptical image measuring apparatus of claim 19, wherein the blood vesselis set in the vicinity of an optic papilla of the eye fundus.
 21. Theoptical image measuring apparatus of claim 19, wherein the photographingpart shares part of optical path with the optical system, furthercomprising: a display configured to display the photographed image ofthe eye fundus by the photographing part; an operation part configuredfor designating the first cross section to the photographed imagedisplayed; and a cross section setting part configured to set the secondcross section based on the first cross section designated and thephotographed image, wherein the scanner carries out the first scan ofthe first cross section designated and carries out the second scan ofthe second cross section set.